{"id":35723,"date":"2025-12-03T06:31:43","date_gmt":"2025-12-03T03:31:43","guid":{"rendered":"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/"},"modified":"2025-12-03T06:31:43","modified_gmt":"2025-12-03T03:31:43","slug":"dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4","status":"publish","type":"post","link":"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/","title":{"rendered":"Do\u011fruluk Neden Aldat\u0131c\u0131d\u0131r? Ger\u00e7ek Metrikler (B\u00f6l\u00fcm 4)"},"content":{"rendered":"<p><body><\/p>\n<header>\n        <!-- H1 etiketi, verilen talimatlara uygun olarak eklenmemi\u015ftir. --><br \/>\n    <\/header>\n<p>    <main><\/p>\n<p>\n            Makine \u00f6\u011frenimi projelerinde model ba\u015far\u0131s\u0131n\u0131 \u00f6l\u00e7mek, \u00e7o\u011fu zaman d\u00fc\u015f\u00fcnd\u00fc\u011f\u00fcm\u00fczden daha karma\u015f\u0131k bir s\u00fcre\u00e7tir. Genellikle ilk akla gelen ve en basit g\u00f6r\u00fcnen metrik <strong>do\u011fruluk (accuracy)<\/strong> olsa da, bu pop\u00fcler g\u00f6sterge ne yaz\u0131k ki s\u0131k s\u0131k yan\u0131lt\u0131c\u0131 sonu\u00e7lar verebilir. Peki, neden sadece do\u011frulu\u011fa g\u00fcvenmek tehlikelidir ve modelimizin ger\u00e7ek performans\u0131n\u0131 anlamak i\u00e7in hangi metrikleri kullanmal\u0131y\u0131z? Bu makalede, do\u011fruluk metriklerinin neden yetersiz kald\u0131\u011f\u0131n\u0131 derinlemesine inceleyecek, ger\u00e7ek d\u00fcnyadaki zorluklara nas\u0131l \u00e7\u00f6z\u00fcm bulabilece\u011fimizi ke\u015ffedece\u011fiz ve modellerimizi daha sa\u011flam bir \u015fekilde de\u011ferlendirmek i\u00e7in kullanabilece\u011fimiz alternatif metrikleri ad\u0131m ad\u0131m \u00f6\u011frenece\u011fiz. \u00d6zellikle dengesiz veri k\u00fcmeleriyle \u00e7al\u0131\u015f\u0131rken do\u011fru de\u011ferlendirme metriklerini se\u00e7mek, projenizin ba\u015far\u0131s\u0131 i\u00e7in hayati \u00f6neme sahiptir; aksi takdirde, &#8220;m\u00fckemmel&#8221; g\u00f6r\u00fcnen bir modelin ger\u00e7ekte hi\u00e7bir i\u015fe yaramad\u0131\u011f\u0131n\u0131 fark edebilirsiniz.\n        <\/p>\n<p>\n            Do\u011fruluk, bir s\u0131n\u0131fland\u0131rma modelinin do\u011fru tahminlerinin toplam tahminlere oran\u0131 olarak tan\u0131mlan\u0131r. Yani, modelin ka\u00e7 \u00f6rne\u011fi do\u011fru bir \u015fekilde s\u0131n\u0131fland\u0131rd\u0131\u011f\u0131n\u0131 g\u00f6sterir. Bu tan\u0131m kula\u011fa olduk\u00e7a mant\u0131kl\u0131 gelse de, \u00f6zellikle veri k\u00fcmenizdeki s\u0131n\u0131f da\u011f\u0131l\u0131m\u0131 e\u015fit olmad\u0131\u011f\u0131nda, yani bir s\u0131n\u0131f di\u011ferine g\u00f6re \u00e7ok daha az say\u0131da \u00f6rne\u011fe sahip oldu\u011funda sorunlar ba\u015f g\u00f6stermeye ba\u015flar. \u00d6rne\u011fin, bir hastal\u0131k te\u015fhis modelinde, sa\u011fl\u0131kl\u0131 insan say\u0131s\u0131 hasta insan say\u0131s\u0131ndan kat kat fazla olabilir. Bu durumda, modelin her zaman &#8220;sa\u011fl\u0131kl\u0131&#8221; tahmininde bulunmas\u0131, %99&#8217;luk bir do\u011fruluk oran\u0131na ula\u015fmas\u0131n\u0131 sa\u011flayabilir. Ancak bu, modelin hastal\u0131\u011f\u0131 tespit etme yetene\u011fi hakk\u0131nda bize hi\u00e7bir bilgi vermez, hatta bu yetene\u011fin tamamen yok oldu\u011funu gizleyebilir. \u0130\u015fte bu y\u00fczden, sadece do\u011frulu\u011fa bakmak, buzda\u011f\u0131n\u0131n g\u00f6r\u00fcnen k\u0131sm\u0131yla yetinmek gibidir. As\u0131l \u00f6nemli olan, suyun alt\u0131nda yatan ve modelin kritik durumlarda nas\u0131l davrand\u0131\u011f\u0131n\u0131 g\u00f6steren di\u011fer metriklerdir.\n        <\/p>\n<p>\n            Bu yan\u0131lt\u0131c\u0131 durumlar\u0131 anlamak i\u00e7in, makine \u00f6\u011freniminde s\u0131k\u00e7a kullan\u0131lan bir kavram olan <strong>Karma\u015f\u0131kl\u0131k Matrisi (Confusion Matrix)<\/strong>&#8216;ne a\u015fina olmam\u0131z gerekir. Bu matris, bir s\u0131n\u0131fland\u0131rma modelinin tahminlerinin ayr\u0131nt\u0131l\u0131 bir \u00f6zetini sunar ve do\u011fru veya yanl\u0131\u015f olarak s\u0131n\u0131fland\u0131r\u0131lan \u00f6rnekleri d\u00f6rt ana kategoriye ay\u0131r\u0131r: Do\u011fru Pozitif (True Positive &#8211; TP), Do\u011fru Negatif (True Negative &#8211; TN), Yanl\u0131\u015f Pozitif (False Positive &#8211; FP) ve Yanl\u0131\u015f Negatif (False Negative &#8211; FN). Bu d\u00f6rt temel ta\u015f, do\u011frulu\u011fun \u00f6tesine ge\u00e7erek modelin g\u00fc\u00e7l\u00fc ve zay\u0131f y\u00f6nlerini ortaya koyan di\u011fer t\u00fcm metriklerin temelini olu\u015fturur. \u00d6rne\u011fin, bir spam filtresi d\u00fc\u015f\u00fcn\u00fcn: Ger\u00e7ekten spam olan bir e-postay\u0131 (pozitif) do\u011fru tahmin etti\u011finde TP; spam olmayan bir e-postay\u0131 (negatif) do\u011fru tahmin etti\u011finde TN; spam olmayan bir e-postay\u0131 yanl\u0131\u015fl\u0131kla spam olarak i\u015faretledi\u011finde FP; ve ger\u00e7ekten spam olan bir e-postay\u0131 g\u00f6zden ka\u00e7\u0131rd\u0131\u011f\u0131nda FN durumu ortaya \u00e7\u0131kar. Bu matrisi anlamak, modelinizin performans\u0131n\u0131 sadece tek bir say\u0131ya indirgemek yerine, \u00e7ok boyutlu bir perspektiften de\u011ferlendirmenizi sa\u011flar.\n        <\/p>\n<p>\n            Dolay\u0131s\u0131yla, &#8220;do\u011fruluk neden yalan s\u00f6yler?&#8221; sorusunun cevab\u0131 olduk\u00e7a basittir: \u00c7\u00fcnk\u00fc karma\u015f\u0131k ger\u00e7ekli\u011fi tek bir say\u0131ya indirger ve \u00f6zellikle dengesiz veri k\u00fcmelerinde modelin kritik hatalar\u0131n\u0131 gizleyebilir. Bu durum, modelin \u00fcretim ortam\u0131nda beklenmedik ve hatta zararl\u0131 sonu\u00e7lar do\u011furmas\u0131na yol a\u00e7abilir. Bir bankan\u0131n sahtekarl\u0131k tespit sisteminde veya bir otonom arac\u0131n yaya tan\u0131ma algoritmas\u0131nda y\u00fcksek do\u011fruluk oran\u0131na sahip olmak, e\u011fer sistem kritik hatalar\u0131 g\u00f6zden ka\u00e7\u0131r\u0131yorsa hi\u00e7bir anlam ifade etmez. \u0130\u015fte bu noktada, modelin farkl\u0131 t\u00fcrdeki hatalara kar\u015f\u0131 ne kadar hassas oldu\u011funu g\u00f6steren, daha \u00f6zel ve ba\u011flama duyarl\u0131 metrikler devreye girer. Bu metrikler sayesinde, modelin yaln\u0131zca genel do\u011frulu\u011funu de\u011fil, ayn\u0131 zamanda belirli s\u0131n\u0131fland\u0131rma g\u00f6revlerindeki inceliklerini de de\u011ferlendirebiliriz. \u0130lerleyen b\u00f6l\u00fcmlerde bu kritik metrikleri ve bunlar\u0131n ger\u00e7ek d\u00fcnya senaryolar\u0131nda nas\u0131l kullan\u0131ld\u0131\u011f\u0131n\u0131 ayr\u0131nt\u0131l\u0131 olarak inceleyece\u011fiz.\n        <\/p>\n<h2 id=\"karmasiklik-matrisi-temelli-metrikler\">Karma\u015f\u0131kl\u0131k Matrisi (Confusion Matrix) Temelli Metrikler: Hassasiyet, Duyarl\u0131l\u0131k ve F1 Skoru Nas\u0131l \u00c7al\u0131\u015f\u0131r?<\/h2>\n<p>\n            Makine \u00f6\u011frenimi modellerinin performans\u0131n\u0131 do\u011fru bir \u015fekilde anlamak i\u00e7in, sadece do\u011frulu\u011fa g\u00fcvenmek yetersizdir. Daha \u00f6nce de belirtti\u011fimiz gibi, dengesiz veri k\u00fcmeleri gibi durumlarda do\u011fruluk, modelin ger\u00e7ek ba\u015far\u0131s\u0131n\u0131 yanl\u0131\u015f yans\u0131tabilir. \u0130\u015fte bu noktada, modelimizin ne t\u00fcr hatalar yapt\u0131\u011f\u0131n\u0131 ve hangi t\u00fcr do\u011fru tahminleri ger\u00e7ekle\u015ftirdi\u011fini ayr\u0131nt\u0131l\u0131 olarak g\u00f6steren <strong>Karma\u015f\u0131kl\u0131k Matrisi (Confusion Matrix)<\/strong> devreye girer. Bu matris, temelde d\u00f6rt temel bile\u015fene sahiptir ve di\u011fer \u00f6nemli metriklerin hesaplanmas\u0131nda birincil kaynakt\u0131r. \u015eimdi bu bile\u015fenleri ve bunlardan t\u00fcreyen kritik metrikleri daha yak\u0131ndan inceleyelim.\n        <\/p>\n<ul>\n<li><strong>Do\u011fru Pozitif (True Positive &#8211; TP):<\/strong> Modelin pozitif olarak tahmin etti\u011fi ve ger\u00e7ekte de pozitif olan durumlar. \u00d6rne\u011fin, hasta olan bir ki\u015fiyi do\u011fru bir \u015fekilde &#8220;hasta&#8221; olarak te\u015fhis etmek.<\/li>\n<li><strong>Do\u011fru Negatif (True Negative &#8211; TN):<\/strong> Modelin negatif olarak tahmin etti\u011fi ve ger\u00e7ekte de negatif olan durumlar. \u00d6rne\u011fin, sa\u011fl\u0131kl\u0131 olan bir ki\u015fiyi do\u011fru bir \u015fekilde &#8220;sa\u011fl\u0131kl\u0131&#8221; olarak te\u015fhis etmek.<\/li>\n<li><strong>Yanl\u0131\u015f Pozitif (False Positive &#8211; FP):<\/strong> Modelin pozitif olarak tahmin etti\u011fi ancak ger\u00e7ekte negatif olan durumlar (Tip I Hatas\u0131). \u00d6rne\u011fin, sa\u011fl\u0131kl\u0131 bir ki\u015fiyi yanl\u0131\u015fl\u0131kla &#8220;hasta&#8221; olarak te\u015fhis etmek. Buna &#8220;Type I Error&#8221; da denir ve bir alarm\u0131n yalan yere \u00e7almas\u0131 gibi d\u00fc\u015f\u00fcn\u00fclebilir.<\/li>\n<li><strong>Yanl\u0131\u015f Negatif (False Negative &#8211; FN):<\/strong> Modelin negatif olarak tahmin etti\u011fi ancak ger\u00e7ekte pozitif olan durumlar (Tip II Hatas\u0131). \u00d6rne\u011fin, hasta bir ki\u015fiyi yanl\u0131\u015fl\u0131kla &#8220;sa\u011fl\u0131kl\u0131&#8221; olarak te\u015fhis etmek. Bu, genellikle en maliyetli hata t\u00fcr\u00fcd\u00fcr, \u00e7\u00fcnk\u00fc \u00f6nemli bir olay\u0131n g\u00f6zden ka\u00e7\u0131r\u0131lmas\u0131 anlam\u0131na gelir (\u00f6rn: kanser hastas\u0131n\u0131 sa\u011fl\u0131kl\u0131 sanmak).<\/li>\n<\/ul>\n<p>\n            Bu d\u00f6rt temel bile\u015fen \u0131\u015f\u0131\u011f\u0131nda, model performans\u0131n\u0131 daha anlaml\u0131 hale getiren \u00fc\u00e7 ana metrik bulunmaktad\u0131r: Hassasiyet (Precision), Duyarl\u0131l\u0131k (Recall) ve F1 Skoru.\n        <\/p>\n<h3>Hassasiyet (Precision): Modelin Pozitif Tahminlerine Ne Kadar G\u00fcvenebiliriz?<\/h3>\n<p>\n            <strong>Hassasiyet (Precision)<\/strong>, modelin pozitif olarak tahmin etti\u011fi durumlardan ne kadar\u0131n\u0131n ger\u00e7ekten pozitif oldu\u011funu \u00f6l\u00e7er. Di\u011fer bir deyi\u015fle, &#8220;Modelin pozitif dedi\u011fi ka\u00e7 \u015fey ger\u00e7ekten pozitif \u00e7\u0131kt\u0131?&#8221; sorusunun cevab\u0131d\u0131r. Form\u00fcl\u00fc \u015f\u00f6yledir:\n        <\/p>\n<p>\n            <code>Precision = TP \/ (TP + FP)<\/code>\n        <\/p>\n<p>\n            Hassasiyet, \u00f6zellikle yanl\u0131\u015f pozitiflerin maliyetinin y\u00fcksek oldu\u011fu durumlarda kritik \u00f6neme sahiptir. \u00d6rne\u011fin, bir spam filtresinde, me\u015fru bir e-postan\u0131n yanl\u0131\u015fl\u0131kla spam olarak i\u015faretlenmesi (FP), kullan\u0131c\u0131n\u0131n \u00f6nemli bir mesaj\u0131 ka\u00e7\u0131rmas\u0131na neden olabilir. Bu senaryoda y\u00fcksek hassasiyet, kullan\u0131c\u0131n\u0131n \u00f6nemli e-postalar\u0131n\u0131 g\u00fcvenle almas\u0131n\u0131 sa\u011flar. Benzer \u015fekilde, bir arama motoru sonu\u00e7lar\u0131nda alakas\u0131z bir sonucun g\u00f6sterilmesi de bir FP&#8217;dir. Kullan\u0131c\u0131 deneyimi i\u00e7in hassasiyetin y\u00fcksek olmas\u0131 istenir.\n        <\/p>\n<h3>Duyarl\u0131l\u0131k (Recall) \/ Geri \u00c7a\u011f\u0131rma Oran\u0131: Model Kritik Durumlar\u0131 Ne Kadar \u0130yi Yakal\u0131yor?<\/h3>\n<p>\n            <strong>Duyarl\u0131l\u0131k (Recall)<\/strong>, bazen <strong>Geri \u00c7a\u011f\u0131rma Oran\u0131<\/strong> veya <strong>Hassasiyet (Sensitivity)<\/strong> olarak da adland\u0131r\u0131l\u0131r, ger\u00e7ekte pozitif olan t\u00fcm durumlardan modelin ne kadar\u0131n\u0131 do\u011fru bir \u015fekilde pozitif olarak tespit edebildi\u011fini \u00f6l\u00e7er. Yani, &#8220;Ger\u00e7ekten pozitif olanlar\u0131n ka\u00e7 tanesini model yakalayabildi?&#8221; sorusunun cevab\u0131d\u0131r. Form\u00fcl\u00fc \u015f\u00f6yledir:\n        <\/p>\n<p>\n            <code>Recall = TP \/ (TP + FN)<\/code>\n        <\/p>\n<p>\n            Duyarl\u0131l\u0131k, \u00f6zellikle yanl\u0131\u015f negatiflerin (FN) maliyetinin \u00e7ok y\u00fcksek oldu\u011fu durumlarda hayati \u00f6nem ta\u015f\u0131r. \u00d6rne\u011fin, bir kanser te\u015fhis sisteminde, ger\u00e7ekten kanserli olan bir hastan\u0131n &#8220;sa\u011fl\u0131kl\u0131&#8221; olarak yanl\u0131\u015f te\u015fhis edilmesi (FN), tedaviye ge\u00e7 kal\u0131nmas\u0131na ve ciddi sonu\u00e7lara yol a\u00e7abilir. Bu gibi durumlarda, modelin m\u00fcmk\u00fcn oldu\u011funca \u00e7ok hastay\u0131 tespit etmesi (y\u00fcksek duyarl\u0131l\u0131k) hedeflenir, hatta bu, baz\u0131 sa\u011fl\u0131kl\u0131 ki\u015filerin yanl\u0131\u015fl\u0131kla kanserli olarak etiketlenmesi (FP) pahas\u0131na bile olsa. Bir sahtekarl\u0131k tespit sisteminde de, ger\u00e7ek bir sahtekarl\u0131\u011f\u0131n g\u00f6zden ka\u00e7\u0131r\u0131lmas\u0131 (FN) finansal kay\u0131plara yol a\u00e7aca\u011f\u0131 i\u00e7in duyarl\u0131l\u0131k kritiktir.\n        <\/p>\n<h3>F1 Skoru: Hassasiyet ve Duyarl\u0131l\u0131k Aras\u0131ndaki Dengeyi Bulmak<\/h3>\n<p>\n            \u00c7o\u011fu ger\u00e7ek d\u00fcnya senaryosunda, y\u00fcksek hassasiyet ve y\u00fcksek duyarl\u0131l\u0131k aras\u0131nda bir denge kurmak gerekir. \u00c7\u00fcnk\u00fc bu iki metrik genellikle birbiriyle \u00e7eli\u015fir: Birini art\u0131rmaya \u00e7al\u0131\u015ft\u0131\u011f\u0131n\u0131zda di\u011feri d\u00fc\u015fme e\u011filiminde olabilir. \u0130\u015fte bu dengeyi \u00f6l\u00e7mek i\u00e7in <strong>F1 Skoru<\/strong> kullan\u0131l\u0131r. F1 skoru, hassasiyet ve duyarl\u0131l\u0131\u011f\u0131n harmonik ortalamas\u0131d\u0131r ve \u00f6zellikle dengesiz veri k\u00fcmelerinde model performans\u0131n\u0131 de\u011ferlendirmek i\u00e7in \u00e7ok daha dengeli bir \u00f6l\u00e7\u00fct sunar.\n        <\/p>\n<p>\n            <code>F1 Skoru = 2 * (Precision * Recall) \/ (Precision + Recall)<\/code>\n        <\/p>\n<p>\n            F1 skoru, hem FP hem de FN&#8217;yi dikkate ald\u0131\u011f\u0131 i\u00e7in, modelin genel performans\u0131n\u0131 tek bir say\u0131 ile \u00f6zetlemek istedi\u011fimizde olduk\u00e7a faydal\u0131d\u0131r. Her iki metri\u011fin de y\u00fcksek oldu\u011fu durumlarda F1 skoru da y\u00fcksek \u00e7\u0131kar. E\u011fer bir metrik (\u00f6rne\u011fin hassasiyet) \u00e7ok d\u00fc\u015f\u00fckse, F1 skoru da d\u00fc\u015fer. Bu nedenle, F1 skoru, \u00f6zellikle pozitif s\u0131n\u0131f\u0131n tespit edilmesinin \u00f6nemli oldu\u011fu ve veri k\u00fcmesinin dengesiz oldu\u011fu s\u0131n\u0131fland\u0131rma g\u00f6revlerinde tercih edilen bir metriktir.\n        <\/p>\n<div class=\"expert-tip\">\n            Uzman \u0130pucu: Hangi metri\u011fin sizin i\u00e7in daha \u00f6nemli oldu\u011funu belirlemek, projenizin i\u015f hedefleri ve yanl\u0131\u015f tahminlerin maliyetine ba\u011fl\u0131d\u0131r. Yanl\u0131\u015f pozitiflerin mi, yoksa yanl\u0131\u015f negatiflerin mi daha b\u00fcy\u00fck bir risk ta\u015f\u0131d\u0131\u011f\u0131n\u0131 iyi analiz etmelisiniz. Bu karar, modelinizi optimize ederken hangi y\u00f6ne a\u011f\u0131rl\u0131k vermeniz gerekti\u011fini belirleyecektir.\n        <\/div>\n<p>\n            \u015eimdi bu metrikleri Python&#8217;da basit bir \u00f6rnekle nas\u0131l hesaplayabilece\u011fimize bakal\u0131m. Diyelim ki, elimizde bir modelin tahminleri ve ger\u00e7ek etiketleri var.\n        <\/p>\n<pre><code class=\"language-python\">\nfrom sklearn.metrics import confusion_matrix, precision_score, recall_score, f1_score\n\n# Ger\u00e7ek etiketler (true labels)\ny_true = [0, 1, 0, 1, 0, 0, 1, 0, 1, 1]\n# Modelin tahminleri (predicted labels)\ny_pred = [0, 1, 0, 0, 0, 1, 1, 0, 1, 1]\n\n# Karma\u015f\u0131kl\u0131k Matrisi olu\u015fturma\ncm = confusion_matrix(y_true, y_pred)\nprint(\"Karma\u015f\u0131kl\u0131k Matrisi:\\n\", cm)\n\n# Matristen TP, TN, FP, FN de\u011ferlerini \u00e7\u0131karma\n# cm[0,0] = TN (0'\u0131 0 tahmin etti)\n# cm[0,1] = FP (0'\u0131 1 tahmin etti)\n# cm[1,0] = FN (1'i 0 tahmin etti)\n# cm[1,1] = TP (1'i 1 tahmin etti)\n\nTN, FP, FN, TP = cm.ravel()\nprint(f\"TP: {TP}, TN: {TN}, FP: {FP}, FN: {FN}\")\n\n# Do\u011fruluk (Accuracy) hesaplama\naccuracy = (TP + TN) \/ (TP + TN + FP + FN)\nprint(f\"Do\u011fruluk (Accuracy): {accuracy:.2f}\")\n\n# Hassasiyet (Precision) hesaplama\nprecision = precision_score(y_true, y_pred)\nprint(f\"Hassasiyet (Precision): {precision:.2f}\")\n\n# Duyarl\u0131l\u0131k (Recall) hesaplama\nrecall = recall_score(y_true, y_pred)\nprint(f\"Duyarl\u0131l\u0131k (Recall): {recall:.2f}\")\n\n# F1 Skoru hesaplama\nf1 = f1_score(y_true, y_pred)\nprint(f\"F1 Skoru: {f1:.2f}\")\n\n# \u00c7\u0131kt\u0131 \u00f6rne\u011fi:\n# Karma\u015f\u0131kl\u0131k Matrisi:\n#  [[4 1]\n#  [1 4]]\n# TP: 4, TN: 4, FP: 1, FN: 1\n# Do\u011fruluk (Accuracy): 0.80\n# Hassasiyet (Precision): 0.80\n# Duyarl\u0131l\u0131k (Recall): 0.80\n# F1 Skoru: 0.80\n        <\/pre>\n<p><\/code><\/p>\n<p>\n            Yukar\u0131daki \u00f6rnekte, modelin tahminlerini ve ger\u00e7ek de\u011ferleri kullanarak Karma\u015f\u0131kl\u0131k Matrisi'ni ve di\u011fer metrikleri hesaplad\u0131k. G\u00f6rd\u00fc\u011f\u00fcn\u00fcz gibi, <code>sklearn.metrics<\/code> k\u00fct\u00fcphanesi bu hesaplamalar\u0131 olduk\u00e7a basitle\u015ftiriyor. Bu metrikleri anlamak ve do\u011fru senaryolarda kullanmak, modelinizin sadece \"do\u011fru\" olup olmad\u0131\u011f\u0131n\u0131 de\u011fil, ayn\u0131 zamanda ne kadar g\u00fcvenilir ve etkili oldu\u011funu da ortaya koyar. Bir sonraki b\u00f6l\u00fcmde, s\u0131n\u0131fland\u0131rma e\u015fiklerinin \u00f6tesine ge\u00e7erek daha geli\u015fmi\u015f metrikleri ve dengesiz veri k\u00fcmeleriyle ba\u015fa \u00e7\u0131kma stratejilerini ele alaca\u011f\u0131z. Bu sayede, modelinizin performans\u0131n\u0131 en ince ayr\u0131nt\u0131s\u0131na kadar de\u011ferlendirebilecek donan\u0131ma sahip olacaks\u0131n\u0131z.\n        <\/p>\n<h2 id=\"siniflandirma-esiklerinin-otesinde\">S\u0131n\u0131fland\u0131rma E\u015fiklerinin \u00d6tesinde: ROC E\u011frisi, AUC ve Dengesiz Veri K\u00fcmeleri \u0130\u00e7in \u0130leri Metrikler<\/h2>\n<p>\n            S\u0131n\u0131fland\u0131rma modelleri genellikle bir tahmin olas\u0131l\u0131\u011f\u0131 \u00fcretir ve ard\u0131ndan bu olas\u0131l\u0131\u011f\u0131 belirli bir e\u015fik de\u011feriyle (genellikle 0.5) kar\u015f\u0131la\u015ft\u0131rarak nihai bir s\u0131n\u0131fland\u0131rma karar\u0131 verir. Ancak bu e\u015fik de\u011feri sabittir ve \u00e7o\u011fu zaman modelin performans\u0131n\u0131n tamam\u0131n\u0131 yans\u0131tmayabilir. Modeli daha derinlemesine anlamak ve farkl\u0131 e\u015fik de\u011ferlerindeki davran\u0131\u015f\u0131n\u0131 incelemek i\u00e7in <strong>ROC E\u011frisi (Receiver Operating Characteristic Curve)<\/strong> ve <strong>AUC (Area Under the Curve)<\/strong> gibi daha geli\u015fmi\u015f metrikler kullan\u0131r\u0131z. Ayr\u0131ca, dengesiz veri k\u00fcmelerinin getirdi\u011fi zorluklar\u0131 a\u015fmak i\u00e7in de \u00f6zel stratejiler ve metrikler mevcuttur.\n        <\/p>\n<h3>ROC E\u011frisi ve AUC De\u011feri: S\u0131n\u0131fland\u0131rma E\u015fiklerinin \u00d6tesine Nas\u0131l Bakar\u0131z?<\/h3>\n<p>\n            Bir s\u0131n\u0131fland\u0131rma modelinin \u00e7\u0131kt\u0131s\u0131 genellikle bir olas\u0131l\u0131k de\u011feri oldu\u011fundan, bu olas\u0131l\u0131k de\u011ferini hangi e\u015fikte pozitif olarak kabul edece\u011fimiz \u00f6nemlidir. \u00d6rne\u011fin, 0.5'in \u00fczerindeki bir olas\u0131l\u0131\u011f\u0131 pozitif s\u0131n\u0131f olarak kabul edebiliriz. Ancak bu e\u015fik de\u011feri de\u011fi\u015ftirilirse (\u00f6rne\u011fin 0.3 veya 0.7), modelin TP, FP, TN ve FN de\u011ferleri de de\u011fi\u015fir. ROC e\u011frisi, bu e\u015fik de\u011ferleri de\u011fi\u015ftik\u00e7e modelin <strong>Do\u011fru Pozitif Oran\u0131 (True Positive Rate - TPR, yani Recall)<\/strong> ile <strong>Yanl\u0131\u015f Pozitif Oran\u0131 (False Positive Rate - FPR)<\/strong> aras\u0131ndaki ili\u015fkiyi g\u00f6steren bir grafiksel ara\u00e7t\u0131r.\n        <\/p>\n<ul>\n<li><strong>Do\u011fru Pozitif Oran\u0131 (TPR - Recall \/ Duyarl\u0131l\u0131k):<\/strong> Modelin t\u00fcm pozitifleri ne kadar iyi yakalad\u0131\u011f\u0131n\u0131 g\u00f6sterir (TP \/ (TP + FN)). Y ekseninde yer al\u0131r.<\/li>\n<li><strong>Yanl\u0131\u015f Pozitif Oran\u0131 (FPR):<\/strong> Modelin t\u00fcm negatiflerden ne kadar\u0131n\u0131 yanl\u0131\u015fl\u0131kla pozitif olarak i\u015faretledi\u011fini g\u00f6sterir (FP \/ (FP + TN)). X ekseninde yer al\u0131r.<\/li>\n<\/ul>\n<p>\n            ROC e\u011frisi, farkl\u0131 s\u0131n\u0131fland\u0131rma e\u015fiklerinde TPR'nin FPR'ye kar\u015f\u0131 \u00e7izilmesiyle olu\u015fur. \u0130deal bir model, sol \u00fcst k\u00f6\u015feye (FPR=0, TPR=1) yak\u0131n bir e\u011friye sahip olacakt\u0131r, \u00e7\u00fcnk\u00fc bu, modelin t\u00fcm pozitifleri yakalarken hi\u00e7bir yanl\u0131\u015f pozitif yapmad\u0131\u011f\u0131 anlam\u0131na gelir. K\u00f6\u015fegen \u00fczerindeki d\u00fcz bir \u00e7izgi ise rastgele bir s\u0131n\u0131fland\u0131r\u0131c\u0131y\u0131 temsil eder.\n        <\/p>\n<p>\n            <strong>AUC (Area Under the Curve)<\/strong>, ROC e\u011frisinin alt\u0131nda kalan aland\u0131r. Bu alan\u0131n de\u011feri 0 ile 1 aras\u0131nda de\u011fi\u015fir. AUC de\u011feri ne kadar y\u00fcksekse (1'e ne kadar yak\u0131nsa), modelin pozitif ve negatif s\u0131n\u0131flar\u0131 ay\u0131rt etme yetene\u011fi o kadar iyidir. Bir modelin AUC de\u011feri 0.5 ise, modelin rastgele tahmin yapmaktan fark\u0131 yoktur. AUC, modelin t\u00fcm olas\u0131 s\u0131n\u0131fland\u0131rma e\u015fiklerindeki genel performans\u0131n\u0131 \u00f6zetleyen tek bir say\u0131d\u0131r ve \u00f6zellikle dengesiz veri k\u00fcmelerinde do\u011fruluktan \u00e7ok daha g\u00fcvenilir bir \u00f6l\u00e7\u00fctt\u00fcr. \u00c7\u00fcnk\u00fc s\u0131n\u0131f da\u011f\u0131l\u0131m\u0131ndan etkilenmez.\n        <\/p>\n<div class=\"expert-tip\">\n            Uzman \u0130pucu: ROC AUC, modelin s\u0131n\u0131fland\u0131rma e\u015fi\u011finden ba\u011f\u0131ms\u0131z olarak ne kadar iyi bir ay\u0131r\u0131c\u0131 oldu\u011funu g\u00f6sterir. Bu, \u00f6zellikle klinik te\u015fhis, sahtekarl\u0131k tespiti veya reklam t\u0131klama tahmini gibi senaryolarda, farkl\u0131 e\u015fiklerin farkl\u0131 i\u015f sonu\u00e7lar\u0131 do\u011furabilece\u011fi durumlarda son derece de\u011ferlidir.\n        <\/div>\n<h3>Dengesiz Veri K\u00fcmeleri \u0130\u00e7in \u0130leri Metrikler ve Stratejiler<\/h3>\n<p>\n            Dengesiz veri k\u00fcmeleri, makine \u00f6\u011frenimi projelerinde kar\u015f\u0131la\u015f\u0131lan en b\u00fcy\u00fck zorluklardan biridir. Bir s\u0131n\u0131f\u0131n di\u011ferinden \u00e7ok daha az \u00f6rne\u011fe sahip olmas\u0131, modelin \u00e7o\u011funluk s\u0131n\u0131f\u0131na \"tarafl\u0131\" davranmas\u0131na ve az\u0131nl\u0131k s\u0131n\u0131f\u0131n\u0131 g\u00f6zden ka\u00e7\u0131rmas\u0131na neden olabilir. ROC AUC her ne kadar dengesiz veri k\u00fcmeleri i\u00e7in iyi bir g\u00f6sterge olsa da, bazen daha spesifik metrikler ve veri dengeleme stratejileri uygulamak gerekebilir.\n        <\/p>\n<h4>Ek De\u011ferlendirme Metrikleri:<\/h4>\n<ul>\n<li><strong>Kappa Skoru (Cohen's Kappa):<\/strong> \u0130ki g\u00f6zlemci (bu durumda ger\u00e7ek ve tahmin edilen etiketler) aras\u0131ndaki anla\u015fmay\u0131, rastgele anla\u015fmay\u0131 da hesaba katarak \u00f6l\u00e7er. Do\u011fruluktan daha sa\u011flam bir \u00f6l\u00e7\u00fctt\u00fcr, \u00f6zellikle dengesiz s\u0131n\u0131flarda.<\/li>\n<li><strong>Matthews Korelasyon Katsay\u0131s\u0131 (MCC):<\/strong> T\u00fcm d\u00f6rt karma\u015f\u0131kl\u0131k matrisi bile\u015fenini (TP, TN, FP, FN) hesaba katan dengeli bir \u00f6l\u00e7\u00fcmd\u00fcr. -1 ile +1 aras\u0131nda de\u011fi\u015fir ve +1 m\u00fckemmel tahmini, -1 tamamen yanl\u0131\u015f tahmini ve 0 rastgele tahmini g\u00f6sterir. Dengesiz s\u0131n\u0131flarda bile g\u00fcvenilir sonu\u00e7lar verir.<\/li>\n<li><strong>Hassasiyet-Duyarl\u0131l\u0131k E\u011frisi (Precision-Recall Curve - PR Curve):<\/strong> \u00d6zellikle pozitif s\u0131n\u0131f\u0131n nadir oldu\u011fu (dengesiz) veri k\u00fcmelerinde ROC e\u011frisine g\u00f6re daha bilgilendirici olabilir. Bu e\u011fri, farkl\u0131 e\u015fiklerde Precision ve Recall aras\u0131ndaki de\u011fi\u015fimi g\u00f6sterir. Y\u00fcksek duyarl\u0131l\u0131k (recall) elde etmek isterken hassasiyetin ne kadar d\u00fc\u015ft\u00fc\u011f\u00fcn\u00fc veya tersini g\u00f6rselle\u015ftirmeye yard\u0131mc\u0131 olur.<\/li>\n<\/ul>\n<h4>Dengesiz Veri K\u00fcmeleriyle Ba\u015fa \u00c7\u0131kma Stratejileri:<\/h4>\n<p>\n            Modelin sadece metriklerini optimize etmek yerine, veri k\u00fcmesinin kendisini d\u00fczenleyerek de performans art\u0131\u015f\u0131 sa\u011flayabiliriz.\n        <\/p>\n<ol>\n<li><strong>Yeniden \u00d6rnekleme (Resampling):<\/strong>\n<ul>\n<li><strong>A\u015f\u0131r\u0131 \u00d6rnekleme (Oversampling):<\/strong> Az\u0131nl\u0131k s\u0131n\u0131f\u0131ndaki \u00f6rnekleri \u00e7o\u011falt\u0131r. SMOTE (Synthetic Minority Over-sampling Technique) en pop\u00fcler y\u00f6ntemlerden biridir; yeni sentetik \u00f6rnekler olu\u015fturur.<\/li>\n<li><strong>Alt \u00d6rnekleme (Undersampling):<\/strong> \u00c7o\u011funluk s\u0131n\u0131f\u0131ndaki \u00f6rnekleri azalt\u0131r. Bu, veri kayb\u0131na yol a\u00e7abilir ancak e\u011fitim s\u00fcresini h\u0131zland\u0131r\u0131r.<\/li>\n<\/ul>\n<\/li>\n<li><strong>S\u0131n\u0131f A\u011f\u0131rl\u0131klar\u0131 (Class Weights):<\/strong> Modelin e\u011fitim s\u00fcrecinde az\u0131nl\u0131k s\u0131n\u0131f\u0131 \u00f6rneklerine daha fazla a\u011f\u0131rl\u0131k vermesini sa\u011flar. Bu sayede, model az\u0131nl\u0131k s\u0131n\u0131f\u0131n\u0131 yanl\u0131\u015f tahmin etti\u011finde daha b\u00fcy\u00fck bir ceza al\u0131r ve bu s\u0131n\u0131f\u0131 \u00f6\u011frenmeye daha fazla odaklan\u0131r. \u00c7o\u011fu makine \u00f6\u011frenimi k\u00fct\u00fcphanesi (Scikit-learn, TensorFlow, PyTorch) bu \u00f6zelli\u011fi sunar.<\/li>\n<li><strong>\u00d6zel Algoritmalar:<\/strong> Baz\u0131 algoritmalar (\u00f6rne\u011fin LightGBM, XGBoost) dengesiz veri k\u00fcmeleriyle daha iyi ba\u015fa \u00e7\u0131kmak i\u00e7in yerle\u015fik mekanizmalara sahiptir.<\/li>\n<\/ol>\n<p>\n            Yukar\u0131da bahsedilen metrikler ve stratejiler, modelinizin performans\u0131n\u0131 \u00e7ok daha sa\u011flam ve ba\u011flama duyarl\u0131 bir \u015fekilde de\u011ferlendirmenizi sa\u011flar. \u00d6zellikle kritik kararlar al\u0131nan sistemlerde (finans, sa\u011fl\u0131k, g\u00fcvenlik), do\u011fru metrikleri se\u00e7mek ve dengesiz veri k\u00fcmelerinin etkilerini y\u00f6netmek projenin ba\u015far\u0131s\u0131 i\u00e7in vazge\u00e7ilmezdir. \u0130\u015fte bu y\u00fczden, sadece do\u011frulu\u011fa tak\u0131l\u0131p kalmak yerine, modelin t\u00fcm y\u00f6nlerini kapsayan geni\u015f bir de\u011ferlendirme \u00e7er\u00e7evesi benimsemek gereklidir.\n        <\/p>\n<pre><code class=\"language-python\">\nfrom sklearn.metrics import roc_curve, auc, roc_auc_score, cohen_kappa_score, matthews_corrcoef\nimport numpy as np\nimport matplotlib.pyplot as plt # Sadece g\u00f6rselle\u015ftirme i\u00e7in, makalede HTML \u00e7\u0131kt\u0131s\u0131 isteniyor\n\n# Ger\u00e7ek etiketler (true labels) ve tahmin olas\u0131l\u0131klar\u0131 (prediction probabilities)\ny_true_imbalanced = [0, 0, 0, 0, 0, 0, 0, 0, 0, 1] # 9 negatif, 1 pozitif\ny_pred_proba = [0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.95]\n\n# Varsay\u0131lan e\u015fik (0.5) ile tahmin edilen etiketler\ny_pred_default = [1 if p > 0.5 else 0 for p in y_pred_proba]\n\n# Bu durumda, y_pred_default = [0, 0, 0, 0, 0, 1, 1, 1, 1, 1]\n# confusion_matrix(y_true_imbalanced, y_pred_default) -> TN:5, FP:4, FN:0, TP:1\n# Accuracy: (5+1)\/10 = 0.6 (Y\u00fcksek gibi g\u00f6r\u00fcnse de, 4 yanl\u0131\u015f pozitif var!)\n# Precision: 1\/(1+4) = 0.2\n# Recall: 1\/(1+0) = 1.0 (T\u00fcm pozitifleri yakalam\u0131\u015f!)\n# F1-Score: 2 * (0.2 * 1.0) \/ (0.2 + 1.0) = 0.33\n\n# ROC AUC skoru hesaplama\nroc_auc = roc_auc_score(y_true_imbalanced, y_pred_proba)\nprint(f\"ROC AUC Skoru: {roc_auc:.2f}\") # \u00c7\u0131kt\u0131: Yakla\u015f\u0131k 0.94 - Bu, modelin ay\u0131rt etme g\u00fcc\u00fcn\u00fcn y\u00fcksek oldu\u011funu g\u00f6sterir\n\n# \u00d6rnek Kappa Skoru ve MCC hesaplama (ger\u00e7ek etiketler ve ikili tahminler \u00fczerinden)\n# y_pred_default = [1 if p > 0.5 else 0 for p in y_pred_proba]\nkappa = cohen_kappa_score(y_true_imbalanced, y_pred_default)\nmcc = matthews_corrcoef(y_true_imbalanced, y_pred_default)\nprint(f\"Kappa Skoru: {kappa:.2f}\") # D\u00fc\u015f\u00fck \u00e7\u0131kacakt\u0131r, \u00e7\u00fcnk\u00fc dengesizlik var ve varsay\u0131lan e\u015fik \u00e7ok say\u0131da FP \u00fcretiyor\nprint(f\"MCC Skoru: {mcc:.2f}\") # Kappa gibi, bu da dengesizli\u011fi ve e\u015fi\u011fin olumsuz etkisini yans\u0131tacakt\u0131r\n        <\/pre>\n<p><\/code><\/p>\n<p>\n            Yukar\u0131daki kod blo\u011fu, dengesiz bir veri k\u00fcmesi \u00fczerinde modelin performans\u0131n\u0131 ROC AUC, Kappa ve MCC skorlar\u0131 ile nas\u0131l de\u011ferlendirebilece\u011fimizi g\u00f6stermektedir. G\u00f6rd\u00fc\u011f\u00fcn\u00fcz gibi, varsay\u0131lan bir e\u015fik de\u011feri ile bile ROC AUC de\u011feri olduk\u00e7a iyi \u00e7\u0131kabilirken (modelin potansiyelini g\u00f6sterir), Kappa ve MCC gibi metrikler mevcut tahmin stratejisinin ne kadar dengeli oldu\u011funu daha net ortaya koyar. Bu, model geli\u015ftirme s\u00fcrecinde s\u00fcrekli olarak farkl\u0131 metrikleri g\u00f6z \u00f6n\u00fcnde bulundurman\u0131n ve s\u0131n\u0131fland\u0131rma e\u015fi\u011fi optimizasyonunun ne kadar \u00f6nemli oldu\u011funu vurgular.\n        <\/p>\n<h2 id=\"vaka-analizi-sahtekarlik-tespiti\">Ger\u00e7ek D\u00fcnya Senaryosu: Kredi Kart\u0131 Sahtekarl\u0131\u011f\u0131 Tespitinde Yan\u0131lt\u0131c\u0131 Do\u011fruluk ve Do\u011fru Metriklerin G\u00fcc\u00fc<\/h2>\n<p>\n            \u015eimdiye kadar \u00f6\u011frendi\u011fimiz teorik bilgileri ger\u00e7ek bir senaryo \u00fczerinden peki\u015ftirelim: Kredi kart\u0131 sahtekarl\u0131\u011f\u0131 tespiti. Bu, makine \u00f6\u011freniminin en yayg\u0131n ve zorlu uygulama alanlar\u0131ndan biridir ve do\u011frulu\u011fun neden yan\u0131lt\u0131c\u0131 olabilece\u011finin m\u00fckemmel bir \u00f6rne\u011fini sunar. Genellikle, kredi kart\u0131 i\u015flemlerinin \u00e7ok k\u00fc\u00e7\u00fck bir y\u00fczdesi (\u00f6rne\u011fin %0.1 ila %0.5) sahtekarl\u0131kt\u0131r. Bu, a\u015f\u0131r\u0131 derecede dengesiz bir veri k\u00fcmesi anlam\u0131na gelir.\n        <\/p>\n<h3>Problemin Tan\u0131m\u0131: Y\u00fcksek Do\u011fruluk, S\u0131f\u0131r Fayda<\/h3>\n<p>\n            Diyelim ki bir sahtekarl\u0131k tespit modeli geli\u015ftirdik. Modelin g\u00f6revi, yeni bir kredi kart\u0131 i\u015fleminin sahtekarl\u0131k olup olmad\u0131\u011f\u0131n\u0131 tahmin etmek. Veri k\u00fcmemizde 1.000.000 i\u015flem var ve bunlardan sadece 1.000 tanesi (%0.1) sahtekarl\u0131k. E\u011fer bir model her zaman \"sahtekarl\u0131k de\u011fil\" tahmini yaparsa, ne olur?\n        <\/p>\n<ul>\n<li><strong>Do\u011fru Negatif (TN):<\/strong> 999.000 i\u015flem do\u011fru bir \u015fekilde \"sahtekarl\u0131k de\u011fil\" olarak tahmin edilir.<\/li>\n<li><strong>Yanl\u0131\u015f Negatif (FN):<\/strong> 1.000 sahtekarl\u0131k i\u015flemi yanl\u0131\u015fl\u0131kla \"sahtekarl\u0131k de\u011fil\" olarak tahmin edilir.<\/li>\n<li><strong>Do\u011fru Pozitif (TP):<\/strong> 0<\/li>\n<li><strong>Yanl\u0131\u015f Pozitif (FP):<\/strong> 0<\/li>\n<\/ul>\n<p>\n            Bu senaryoda, modelin do\u011frulu\u011fu: <code>(999.000 + 0) \/ 1.000.000 = 0.999<\/code> veya %99.9 olacakt\u0131r. Harika, de\u011fil mi? %99.9 do\u011fruluk! Ancak bu modelin sahtekarl\u0131klar\u0131 tespit etme yetene\u011fi s\u0131f\u0131rd\u0131r. T\u00fcm 1.000 sahtekarl\u0131k i\u015flemini g\u00f6zden ka\u00e7\u0131rm\u0131\u015ft\u0131r. \u0130\u015fte burada do\u011fruluk bize \"yalan s\u00f6yler\". Bu kadar y\u00fcksek bir do\u011fruluk oran\u0131na ra\u011fmen, modelin i\u015f de\u011feri s\u0131f\u0131rd\u0131r, \u00e7\u00fcnk\u00fc ana hedefi olan sahtekarl\u0131\u011f\u0131 tespit etme g\u00f6revinde tamamen ba\u015far\u0131s\u0131z olmu\u015ftur.\n        <\/p>\n<h3>Do\u011fru Metriklerin G\u00fcc\u00fc: Recall (Duyarl\u0131l\u0131k) Neden Bu Kadar \u00d6nemli?<\/h3>\n<p>\n            Sahtekarl\u0131k tespitinde, bir sahtekarl\u0131k i\u015flemini g\u00f6zden ka\u00e7\u0131rman\u0131n (Yanl\u0131\u015f Negatif - FN) maliyeti, me\u015fru bir i\u015flemi yanl\u0131\u015fl\u0131kla sahtekarl\u0131k olarak i\u015faretlemenin (Yanl\u0131\u015f Pozitif - FP) maliyetinden \u00e7ok daha y\u00fcksektir. Milyonlarca dolarl\u0131k kay\u0131plara yol a\u00e7abilir. Bu nedenle, sahtekarl\u0131k tespitinde birincil hedefimiz, m\u00fcmk\u00fcn oldu\u011funca \u00e7ok sahtekarl\u0131k i\u015flemini yakalamak, yani <strong>y\u00fcksek Duyarl\u0131l\u0131k (Recall)<\/strong> elde etmektir.\n        <\/p>\n<p>\n            Y\u00fcksek duyarl\u0131l\u0131k, modelin ger\u00e7ek pozitifleri ne kadar iyi buldu\u011funu g\u00f6sterir. Ancak sadece duyarl\u0131l\u0131\u011fa odaklanmak da yeterli de\u011fildir. A\u015f\u0131r\u0131 y\u00fcksek duyarl\u0131l\u0131k (\u00f6rne\u011fin %100) elde etmek i\u00e7in her i\u015flemi \"sahtekarl\u0131k\" olarak i\u015faretleyen bir model, \u00e7ok say\u0131da me\u015fru i\u015flemi de sahtekarl\u0131k olarak etiketleyebilir (y\u00fcksek FP). Bu da m\u00fc\u015fteri memnuniyetsizli\u011fine, gereksiz g\u00fcvenlik kontrollerine ve operasyonel maliyetlere yol a\u00e7ar. \u0130\u015fte bu y\u00fczden, duyarl\u0131l\u0131k ile <strong>Hassasiyet (Precision)<\/strong> aras\u0131nda dengeli bir uzla\u015fma bulmak kritik \u00f6neme sahiptir. Precision, modelin sahtekarl\u0131k dedi\u011fi i\u015flemlerin ne kadar\u0131n\u0131n ger\u00e7ekten sahtekarl\u0131k oldu\u011funu g\u00f6sterir.\n        <\/p>\n<p>\n            <strong>F1 Skoru<\/strong> veya <strong>Precision-Recall (PR) E\u011frisi<\/strong>, bu dengenin de\u011ferlendirilmesi i\u00e7in ideal metriklerdir. \u00d6zellikle PR e\u011frisi, dengesiz veri k\u00fcmelerinde ROC e\u011frisinden daha anlaml\u0131 olabilir, \u00e7\u00fcnk\u00fc sadece pozitif s\u0131n\u0131f performans\u0131na odaklan\u0131r.\n        <\/p>\n<h4>Uygulamal\u0131 \u00d6rnek ve De\u011ferlendirme:<\/h4>\n<p>\n            Diyelim ki, geli\u015ftirdi\u011fimiz model, 1.000 sahtekarl\u0131k i\u015fleminden 800'\u00fcn\u00fc do\u011fru bir \u015fekilde tespit etti (TP=800), ancak bu s\u0131rada 2.000 me\u015fru i\u015flemi de yanl\u0131\u015fl\u0131kla sahtekarl\u0131k olarak i\u015faretledi (FP=2.000). Modelimiz hala 997.000 me\u015fru i\u015flemi do\u011fru olarak belirledi (TN=997.000).\n        <\/p>\n<ul>\n<li>TP = 800<\/li>\n<li>FN = 1.000 (ger\u00e7ek sahtekarl\u0131k) - 800 (yakalanan sahtekarl\u0131k) = 200<\/li>\n<li>FP = 2.000<\/li>\n<li>TN = 999.000 (ger\u00e7ek me\u015fru) - 2.000 (yanl\u0131\u015f alarm) = 997.000<\/li>\n<\/ul>\n<p>\n            Bu modelin metrikleri \u015f\u00f6yle olacakt\u0131r:\n        <\/p>\n<pre><code class=\"language-python\">\n# Sahtekarl\u0131k Tespit Senaryosu\nTP_fraud = 800\nFN_fraud = 200\nFP_fraud = 2000\nTN_fraud = 997000\n\naccuracy_fraud = (TP_fraud + TN_fraud) \/ (TP_fraud + TN_fraud + FP_fraud + FN_fraud)\nprecision_fraud = TP_fraud \/ (TP_fraud + FP_fraud)\nrecall_fraud = TP_fraud \/ (TP_fraud + FN_fraud)\nf1_fraud = 2 * (precision_fraud * recall_fraud) \/ (precision_fraud + recall_fraud)\n\nprint(f\"Sahtekarl\u0131k Tespit Modeli Metrikleri:\")\nprint(f\"Do\u011fruluk (Accuracy): {accuracy_fraud:.4f}\") # 0.9978 (hala y\u00fcksek!)\nprint(f\"Hassasiyet (Precision): {precision_fraud:.4f}\") # 0.2857 (d\u00fc\u015f\u00fck)\nprint(f\"Duyarl\u0131l\u0131k (Recall): {recall_fraud:.4f}\") # 0.8000 (y\u00fcksek)\nprint(f\"F1 Skoru: {f1_fraud:.4f}\") # 0.4211\n        <\/pre>\n<p><\/code><\/p>\n<p>\n            Bu modelin do\u011frulu\u011fu %99.78'dir, yine olduk\u00e7a y\u00fcksek g\u00f6r\u00fcnmektedir. Ancak, hassasiyet sadece %28.57 iken duyarl\u0131l\u0131k %80'dir. Bu bize ne anlat\u0131r? Model, sahtekarl\u0131klar\u0131n b\u00fcy\u00fck bir k\u0131sm\u0131n\u0131 yakalamay\u0131 ba\u015far\u0131rken (y\u00fcksek duyarl\u0131l\u0131k), her 100 sahtekarl\u0131k tahmininden sadece yakla\u015f\u0131k 28'i ger\u00e7ekten sahtekarl\u0131kt\u0131r (d\u00fc\u015f\u00fck hassasiyet). Kalan 72 tahmin ise yanl\u0131\u015f alarmd\u0131r. \u0130\u015fletme a\u00e7\u0131s\u0131ndan, %80 duyarl\u0131l\u0131k (sahtekarl\u0131klar\u0131n \u00e7o\u011funu yakalamak) \u00e7ok \u00f6nemlidir. %28.57'lik hassasiyet ise, her tespit edilen sahtekarl\u0131k i\u00e7in 3-4 me\u015fru i\u015flemin incelenmesi gerekti\u011fi anlam\u0131na gelir ki bu da kabul edilebilir bir operasyonel maliyet olabilir. Bu metrikler bize, modelin ger\u00e7ek d\u00fcnyadaki etkileri hakk\u0131nda do\u011frulu\u011fun asla veremeyece\u011fi kadar de\u011ferli bilgiler sunar.\n        <\/p>\n<div class=\"expert-tip\">\n            Uzman \u0130pucu: Sahtekarl\u0131k tespit sistemlerinde, modelin e\u015fik de\u011ferini ayarlamak, hassasiyet ve duyarl\u0131l\u0131k aras\u0131ndaki dengeyi y\u00f6netmenin g\u00fc\u00e7l\u00fc bir yoludur. Daha d\u00fc\u015f\u00fck bir e\u015fik, daha fazla sahtekarl\u0131k yakalayabilir (y\u00fcksek recall) ancak daha fazla yanl\u0131\u015f alarma yol a\u00e7ar (d\u00fc\u015f\u00fck precision). \u0130\u015f gereksinimlerine g\u00f6re bu e\u015fi\u011fi optimize etmek, modelin ticari ba\u015far\u0131s\u0131 i\u00e7in kritik \u00f6neme sahiptir.\n        <\/div>\n<h3>Web Tabanl\u0131 Makine \u00d6\u011frenimi Uygulamalar\u0131nda Metrikleri Sunarken Mobil Deneyim Nas\u0131l \u00d6nem Kazan\u0131r?<\/h3>\n<p>\n            Bu t\u00fcr karma\u015f\u0131k metriklerin ve performans analizlerinin sunuldu\u011fu web tabanl\u0131 bir g\u00f6sterge paneli (dashboard) geli\u015ftirirken, kullan\u0131c\u0131 deneyimini, \u00f6zellikle de mobil uyumlulu\u011fu g\u00f6z ard\u0131 etmemek gerekir. Bir veri bilimci veya i\u015f analisti, modelin performans\u0131n\u0131 her yerden, her cihazdan izleyebilmelidir. Karma\u015f\u0131kl\u0131k matrisleri, ROC e\u011frileri veya metrik tablolar\u0131 gibi yo\u011fun g\u00f6rsel ve say\u0131sal veriler, k\u00fc\u00e7\u00fck mobil ekranlarda okunmas\u0131 ve yorumlanmas\u0131 zor olabilir.\n        <\/p>\n<p>\n            Bu nedenle, metrikleri sunarken duyarl\u0131 tasar\u0131m ilkelerine uymak esast\u0131r. \u00d6rne\u011fin, b\u00fcy\u00fck bir tabloyu mobil cihazlarda daha iyi g\u00f6r\u00fcnt\u00fclemek i\u00e7in CSS medya sorgular\u0131 kullan\u0131larak kolonlar\u0131n gizlenmesi, y\u0131\u011f\u0131lmas\u0131 veya sadece en kritik bilgilerin g\u00f6sterilmesi sa\u011flanabilir. Grafikler i\u00e7in etkile\u015fimli k\u00fct\u00fcphaneler (\u00f6rne\u011fin Plotly.js, Chart.js) kullan\u0131labilir, b\u00f6ylece kullan\u0131c\u0131lar verileri yak\u0131nla\u015ft\u0131rabilir veya belirli b\u00f6l\u00fcmler \u00fczerinde detay g\u00f6rebilir.\n        <\/p>\n<pre><code class=\"language-css\">\n\/* Genel tablo stilini tan\u0131mla *\/\ntable {\n  width: 100%;\n  border-collapse: collapse;\n  margin-bottom: 1em;\n}\n\nth, td {\n  border: 1px solid #ddd;\n  padding: 8px;\n  text-align: left;\n}\n\n\/* K\u00fc\u00e7\u00fck ekranlar i\u00e7in medya sorgusu *\/\n@media screen and (max-width: 600px) {\n  table, thead, tbody, th, td, tr {\n    display: block; \/* Tablo elemanlar\u0131n\u0131 blok olarak g\u00f6ster *\/\n  }\n\n  thead tr {\n    position: absolute; \/* Ba\u015fl\u0131k sat\u0131r\u0131n\u0131 gizle *\/\n    top: -9999px;\n    left: -9999px;\n  }\n\n  tr {\n    border: 1px solid #ccc; \/* Her sat\u0131ra \u00e7er\u00e7eve ekle *\/\n    margin-bottom: 10px;\n  }\n\n  td {\n    border: none; \/* H\u00fccre \u00e7er\u00e7evelerini kald\u0131r *\/\n    border-bottom: 1px solid #eee;\n    position: relative;\n    padding-left: 50%; \/* Etiket i\u00e7in yer a\u00e7 *\/\n    text-align: right;\n  }\n\n  td:before {\n    \/* \u00d6zel veri nitelikleri kullanarak etiketleri g\u00f6ster *\/\n    position: absolute;\n    top: 6px;\n    left: 6px;\n    width: 45%;\n    padding-right: 10px;\n    white-space: nowrap;\n    content: attr(data-label); \/* data-label niteli\u011findeki de\u011feri etiket olarak kullan *\/\n    font-weight: bold;\n    text-align: left;\n  }\n}\n        <\/pre>\n<p><\/code><\/p>\n<p>\n            Yukar\u0131daki CSS medya sorgusu \u00f6rne\u011fi, bir HTML tablosunun mobil ekranlarda nas\u0131l daha okunabilir hale getirilebilece\u011fini g\u00f6sterir. Bu t\u00fcr duyarl\u0131 yakla\u015f\u0131mlar, karma\u015f\u0131k makine \u00f6\u011frenimi metriklerinin farkl\u0131 cihazlarda bile anlaml\u0131 ve eri\u015filebilir kalmas\u0131n\u0131 sa\u011flar, b\u00f6ylece i\u015f kararlar\u0131 daha h\u0131zl\u0131 ve do\u011fru bir \u015fekilde al\u0131nabilir. Bu sadece kullan\u0131c\u0131 deneyimini art\u0131rmakla kalmaz, ayn\u0131 zamanda modelin i\u015f de\u011ferini de y\u00fckseltir.\n        <\/p>\n<h2 id=\"sonuc-dogru-metrikleri-secmek\">Sonu\u00e7: Makine \u00d6\u011frenimi Projelerinizde Do\u011fru Metrikleri Se\u00e7menin \u00d6nemi ve S\u0131k\u00e7a Sorulan Sorular<\/h2>\n<p>\n            Makine \u00f6\u011frenimi modellerini de\u011ferlendirme yolculu\u011fumuzun d\u00f6rd\u00fcnc\u00fc b\u00f6l\u00fcm\u00fcnde, do\u011frulu\u011fun neden tek ba\u015f\u0131na yeterli olmad\u0131\u011f\u0131n\u0131 ve ger\u00e7ek d\u00fcnyadaki zorlu senaryolarda bizi nas\u0131l yan\u0131ltabilece\u011fini ayr\u0131nt\u0131l\u0131 olarak ele ald\u0131k. G\u00f6rd\u00fck ki, \u00f6zellikle dengesiz veri k\u00fcmeleriyle kar\u015f\u0131 kar\u015f\u0131ya kald\u0131\u011f\u0131m\u0131zda, sadece do\u011frulu\u011fa g\u00fcvenmek, bir projenin ba\u015far\u0131s\u0131zl\u0131kla sonu\u00e7lanmas\u0131na neden olabilecek kritik hatalar\u0131 gizleyebilir. Karma\u015f\u0131kl\u0131k Matrisi'nin temelini olu\u015fturan TP, TN, FP, FN kavramlar\u0131ndan yola \u00e7\u0131karak Hassasiyet (Precision), Duyarl\u0131l\u0131k (Recall) ve F1 Skoru gibi metriklerin ne anlama geldi\u011fini, hangi durumlarda hangisinin daha \u00f6nemli oldu\u011funu ve aralar\u0131ndaki dengeyi nas\u0131l kuraca\u011f\u0131m\u0131z\u0131 \u00f6\u011frendik.\n        <\/p>\n<p>\n            Ayr\u0131ca, modelin s\u0131n\u0131fland\u0131rma e\u015fi\u011finden ba\u011f\u0131ms\u0131z performans\u0131n\u0131 g\u00f6steren ROC E\u011frisi ve AUC gibi ileri d\u00fczey metrikleri inceledik. Kredi kart\u0131 sahtekarl\u0131\u011f\u0131 tespiti gibi ger\u00e7ek d\u00fcnya vaka analizleri, bu metriklerin pratik de\u011ferini ve i\u015f hedefleriyle nas\u0131l ili\u015fkilendirilece\u011fini a\u00e7\u0131k\u00e7a ortaya koydu. Mobil uyumluluk gibi operasyonel konulara da de\u011finerek, model de\u011ferlendirme sonu\u00e7lar\u0131n\u0131n farkl\u0131 platformlarda nas\u0131l etkili bir \u015fekilde sunulabilece\u011fine dair ipu\u00e7lar\u0131 verdik. Unutulmamal\u0131d\u0131r ki, en iyi metrik, projenizin ba\u011flam\u0131na, i\u015f hedeflerine ve yanl\u0131\u015f tahminlerin potansiyel maliyetlerine en uygun olan metriktir. Bu nedenle, modelinizi de\u011ferlendirirken kapsaml\u0131 bir bak\u0131\u015f a\u00e7\u0131s\u0131 benimsemek ve do\u011fru kararlar almak i\u00e7in birden fazla metri\u011fi birlikte yorumlamak hayati \u00f6nem ta\u015f\u0131r.\n        <\/p>\n<h3 id=\"sikca-sorulan-sorular\">S\u0131k\u00e7a Sorulan Sorular<\/h3>\n<dl>\n<dt><strong>1. Do\u011fruluk her zaman k\u00f6t\u00fc bir metrik midir?<\/strong><\/dt>\n<dd>Hay\u0131r, do\u011fruluk her zaman k\u00f6t\u00fc bir metrik de\u011fildir. S\u0131n\u0131f da\u011f\u0131l\u0131m\u0131n\u0131n dengeli oldu\u011fu ve yanl\u0131\u015f pozitif ile yanl\u0131\u015f negatif maliyetlerinin benzer oldu\u011fu durumlarda do\u011fruluk, modelin genel performans\u0131n\u0131 iyi bir \u015fekilde \u00f6zetleyebilir. Ancak dengesiz veri k\u00fcmelerinde veya belirli hata t\u00fcrlerinin (FP\/FN) daha maliyetli oldu\u011fu durumlarda yetersiz kal\u0131r.<\/dd>\n<dt><strong>2. Hangi metri\u011fi se\u00e7ece\u011fime nas\u0131l karar vermeliyim?<\/strong><\/dt>\n<dd>Metrik se\u00e7imi, projenizin spesifik hedeflerine ve yanl\u0131\u015f tahminlerin (FP\/FN) i\u015finize olan maliyetine ba\u011fl\u0131d\u0131r. \u00d6rne\u011fin, t\u0131bbi te\u015fhislerde (hastal\u0131\u011f\u0131 ka\u00e7\u0131rman\u0131n maliyeti y\u00fcksek) duyarl\u0131l\u0131k (recall) daha \u00f6nemliyken, spam tespitinde (me\u015fru e-postay\u0131 yanl\u0131\u015f i\u015faretlemenin maliyeti y\u00fcksek) hassasiyet (precision) daha kritik olabilir. Dengeli bir g\u00f6r\u00fcn\u00fcm i\u00e7in F1 skoru veya ROC AUC tercih edilebilir.<\/dd>\n<dt><strong>3. Dengesiz veri k\u00fcmesini dengelemek i\u00e7in hangi y\u00f6ntemleri kullanmal\u0131y\u0131m?<\/strong><\/dt>\n<dd>Dengesiz veri k\u00fcmelerini dengelemek i\u00e7in a\u015f\u0131r\u0131 \u00f6rnekleme (oversampling, \u00f6rne\u011fin SMOTE), alt \u00f6rnekleme (undersampling) veya modelin e\u011fitiminde s\u0131n\u0131f a\u011f\u0131rl\u0131klar\u0131 (class weights) kullanma gibi y\u00f6ntemleri d\u00fc\u015f\u00fcnebilirsiniz. Her y\u00f6ntemin avantajlar\u0131 ve dezavantajlar\u0131 vard\u0131r, bu y\u00fczden veri k\u00fcmenize ve modelinize en uygun olan\u0131 bulmak i\u00e7in deneme yapman\u0131z \u00f6nerilir.<\/dd>\n<dt><strong>4. ROC AUC skoru 0.5 ise ne anlama gelir?<\/strong><\/dt>\n<dd>Bir modelin ROC AUC skoru 0.5 ise, bu modelin rastgele tahmin yapmaktan daha iyi performans g\u00f6stermedi\u011fi anlam\u0131na gelir. Yani, modelin pozitif ve negatif s\u0131n\u0131flar\u0131 ay\u0131rt etme yetene\u011fi neredeyse hi\u00e7 yoktur.<\/dd>\n<dt><strong>5. Metriklerimi mobil bir uygulamada veya web sitesinde nas\u0131l etkili bir \u015fekilde sunabilirim?<\/strong><\/dt>\n<dd>Mobil uyumlu (responsive) tasar\u0131m ilkeleri kullanarak metriklerinizi sunmal\u0131s\u0131n\u0131z. B\u00fcy\u00fck tablolar\u0131 k\u00fc\u00e7\u00fck ekranlar i\u00e7in yeniden d\u00fczenlemek (\u00f6rne\u011fin kolonlar\u0131 gizlemek veya y\u0131\u011fmak i\u00e7in CSS medya sorgular\u0131 kullanmak) ve etkile\u015fimli grafikler (zoom, tooltip gibi \u00f6zelliklerle) kullanmak, verilerin farkl\u0131 cihazlarda daha anlaml\u0131 ve eri\u015filebilir olmas\u0131n\u0131 sa\u011flar.<\/dd>\n<\/dl>\n<p>    <\/main><br \/>\n<\/body><\/p>\n","protected":false},"excerpt":{"rendered":"Makine \u00f6\u011frenimi projelerinde model ba\u015far\u0131s\u0131n\u0131 \u00f6l\u00e7mek, \u00e7o\u011fu zaman d\u00fc\u015f\u00fcnd\u00fc\u011f\u00fcm\u00fczden daha karma\u015f\u0131k bir s\u00fcre\u00e7tir. Genellikle ilk akla gelen ve&hellip;","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"csco_page_header_type":"","csco_page_load_nextpost":"","csco_page_subscribe_form":"","csco_page_contact_form":"","footnotes":""},"categories":[1],"tags":[],"class_list":{"0":"post-35723","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-genel","7":"cs-entry","8":"cs-video-wrap"},"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v20.5 (Yoast SEO v25.3.1) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Do\u011fruluk Neden Aldat\u0131c\u0131d\u0131r? Ger\u00e7ek Metrikler (B\u00f6l\u00fcm 4)<\/title>\n<meta name=\"description\" content=\"Makine \u00f6\u011frenimi projelerinde model ba\u015far\u0131s\u0131n\u0131 \u00f6l\u00e7mek, \u00e7o\u011fu zaman d\u00fc\u015f\u00fcnd\u00fc\u011f\u00fcm\u00fczden daha karma\u015f\u0131k bir s\u00fcre\u00e7tir. Genellikle ilk akla gelen ve en basit g\u00f6r\u00fcnen metrik do\u011fruluk (accuracy) olsa da, bu pop\u00fcler g\u00f6sterge ne yaz\u0131k ki s\u0131k s\u0131k yan\u0131lt\u0131c\u0131 sonu\u00e7lar verebilir. Peki, neden sadece do\u011frulu\u011fa g\u00fcvenmek tehlikelidir ve modelimizin ger\u00e7ek performans\u0131n\u0131 anlamak i\u00e7in hangi metrikleri kullanmal\u0131y\u0131z? Bu makalede, do\u011fruluk metriklerinin neden yetersiz kald\u0131\u011f\u0131n\u0131 derinlemesine inceleyecek, ger\u00e7ek d\u00fcnyadaki zorluklara nas\u0131l \u00e7\u00f6z\u00fcm bulabilece\u011fimizi ke\u015ffedece\u011fiz ve modellerimizi daha sa\u011flam bir \u015fekilde de\u011ferlendirmek i\u00e7in kullanabilece\u011fimiz alternatif metrikleri ad\u0131m ad\u0131m \u00f6\u011frenece\u011fiz. \u00d6zellikle dengesiz veri k\u00fcmeleriyle \u00e7al\u0131\u015f\u0131rken do\u011fru de\u011ferlendirme metriklerini se\u00e7mek, projenizin ba\u015far\u0131s\u0131 i\u00e7in hayati \u00f6neme sahiptir; aksi takdirde, &quot;m\u00fckemmel&quot; g\u00f6r\u00fcnen bir modelin ger\u00e7ekte hi\u00e7bir i\u015fe yaramad\u0131\u011f\u0131n\u0131 fark edebilirsiniz.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/\" \/>\n<meta property=\"og:locale\" content=\"tr_TR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Do\u011fruluk Neden Aldat\u0131c\u0131d\u0131r? Ger\u00e7ek Metrikler (B\u00f6l\u00fcm 4)\" \/>\n<meta property=\"og:description\" content=\"Makine \u00f6\u011frenimi projelerinde model ba\u015far\u0131s\u0131n\u0131 \u00f6l\u00e7mek, \u00e7o\u011fu zaman d\u00fc\u015f\u00fcnd\u00fc\u011f\u00fcm\u00fczden daha karma\u015f\u0131k bir s\u00fcre\u00e7tir. Genellikle ilk akla gelen ve en basit g\u00f6r\u00fcnen metrik do\u011fruluk (accuracy) olsa da, bu pop\u00fcler g\u00f6sterge ne yaz\u0131k ki s\u0131k s\u0131k yan\u0131lt\u0131c\u0131 sonu\u00e7lar verebilir. Peki, neden sadece do\u011frulu\u011fa g\u00fcvenmek tehlikelidir ve modelimizin ger\u00e7ek performans\u0131n\u0131 anlamak i\u00e7in hangi metrikleri kullanmal\u0131y\u0131z? Bu makalede, do\u011fruluk metriklerinin neden yetersiz kald\u0131\u011f\u0131n\u0131 derinlemesine inceleyecek, ger\u00e7ek d\u00fcnyadaki zorluklara nas\u0131l \u00e7\u00f6z\u00fcm bulabilece\u011fimizi ke\u015ffedece\u011fiz ve modellerimizi daha sa\u011flam bir \u015fekilde de\u011ferlendirmek i\u00e7in kullanabilece\u011fimiz alternatif metrikleri ad\u0131m ad\u0131m \u00f6\u011frenece\u011fiz. \u00d6zellikle dengesiz veri k\u00fcmeleriyle \u00e7al\u0131\u015f\u0131rken do\u011fru de\u011ferlendirme metriklerini se\u00e7mek, projenizin ba\u015far\u0131s\u0131 i\u00e7in hayati \u00f6neme sahiptir; aksi takdirde, &quot;m\u00fckemmel&quot; g\u00f6r\u00fcnen bir modelin ger\u00e7ekte hi\u00e7bir i\u015fe yaramad\u0131\u011f\u0131n\u0131 fark edebilirsiniz.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/\" \/>\n<meta property=\"og:site_name\" content=\"Kodlar\u0131n Gizemli D\u00fcnyas\u0131\" \/>\n<meta property=\"article:published_time\" content=\"2025-12-03T03:31:43+00:00\" \/>\n<meta name=\"author\" content=\"Fatih Soysal\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Yazan:\" \/>\n\t<meta name=\"twitter:data1\" content=\"Fatih Soysal\" \/>\n\t<meta name=\"twitter:label2\" content=\"Tahmini okuma s\u00fcresi\" \/>\n\t<meta name=\"twitter:data2\" content=\"27 dakika\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/\"},\"author\":{\"name\":\"Fatih Soysal\",\"@id\":\"https:\/\/fatihsoysal.com\/blog\/#\/schema\/person\/002a254750921dcfd568a99e48240dd1\"},\"headline\":\"Do\u011fruluk Neden Aldat\u0131c\u0131d\u0131r? 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Ger\u00e7ek Metrikler (B\u00f6l\u00fcm 4)\",\"isPartOf\":{\"@id\":\"https:\/\/fatihsoysal.com\/blog\/#website\"},\"datePublished\":\"2025-12-03T03:31:43+00:00\",\"description\":\"Makine \u00f6\u011frenimi projelerinde model ba\u015far\u0131s\u0131n\u0131 \u00f6l\u00e7mek, \u00e7o\u011fu zaman d\u00fc\u015f\u00fcnd\u00fc\u011f\u00fcm\u00fczden daha karma\u015f\u0131k bir s\u00fcre\u00e7tir. Genellikle ilk akla gelen ve en basit g\u00f6r\u00fcnen metrik do\u011fruluk (accuracy) olsa da, bu pop\u00fcler g\u00f6sterge ne yaz\u0131k ki s\u0131k s\u0131k yan\u0131lt\u0131c\u0131 sonu\u00e7lar verebilir. Peki, neden sadece do\u011frulu\u011fa g\u00fcvenmek tehlikelidir ve modelimizin ger\u00e7ek performans\u0131n\u0131 anlamak i\u00e7in hangi metrikleri kullanmal\u0131y\u0131z? Bu makalede, do\u011fruluk metriklerinin neden yetersiz kald\u0131\u011f\u0131n\u0131 derinlemesine inceleyecek, ger\u00e7ek d\u00fcnyadaki zorluklara nas\u0131l \u00e7\u00f6z\u00fcm bulabilece\u011fimizi ke\u015ffedece\u011fiz ve modellerimizi daha sa\u011flam bir \u015fekilde de\u011ferlendirmek i\u00e7in kullanabilece\u011fimiz alternatif metrikleri ad\u0131m ad\u0131m \u00f6\u011frenece\u011fiz. \u00d6zellikle dengesiz veri k\u00fcmeleriyle \u00e7al\u0131\u015f\u0131rken do\u011fru de\u011ferlendirme metriklerini se\u00e7mek, projenizin ba\u015far\u0131s\u0131 i\u00e7in hayati \u00f6neme sahiptir; aksi takdirde, \\\"m\u00fckemmel\\\" g\u00f6r\u00fcnen bir modelin ger\u00e7ekte hi\u00e7bir i\u015fe yaramad\u0131\u011f\u0131n\u0131 fark edebilirsiniz.\",\"breadcrumb\":{\"@id\":\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/#breadcrumb\"},\"inLanguage\":\"tr\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/fatihsoysal.com\/blog\/dogruluk-neden-aldaticidir-gercek-metrikler-bolum-4\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Anasayfa\",\"item\":\"https:\/\/fatihsoysal.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Do\u011fruluk Neden Aldat\u0131c\u0131d\u0131r? 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