Sürekli Bir Değişkeni İkiye Ayırmak İçin Entropi Ölçüsünün Kullanımı

Öz

Kanada’daki nüfus temelli araştırmalarda kullanılan 6 maddelik Kessler Psikolojik Sıkıntı Ölçeği (K6) için literatürde çok sayıda kesme noktası belirlenmiştir. Kesme noktasının seçimine ilişkin gerekçe çoğu zaman ya hiç belirtilmemekte ya da yetersiz biçimde belgelendirilmektedir. Bu makalenin amacı, yalnızca K6 puanlarının dağılımını kullanarak seçim gerekçesini belirlemeye yönelik yeni bir yaklaşım sunmaktır. Öncelikle, gözlemlenen puanların 25 K6 kategorisindeki dağılımından bir entropi ölçüsü hesaplanmış; ardından tüm olası kesme noktaları (iki kategori) için aynı hesaplama yapılmıştır. Bu uygulama, Kanada Toplum Sağlığı Araştırması (KTSA)’nın dört döngüsünden (2005, 2007–2008, 2009–2010 ve 2013–2014) elde edilen Quebec verileri kullanılarak gerçekleştirilmiştir. Seçilen kesme noktası, 25 kategorinin tamamı için elde edilen bilgi miktarına benzer düzeyde bilgi sağlayan noktadır. KTSA’nın dört döngüsü için belirlenen kesme noktası 5/6 olmuştur. Bu yöntem, bir kesme noktasının önceki çalışmalarda kullanılmış olmasına dayanarak benimsenmesi yerine, ampirik olarak belirlenmesinin önemini vurgulamaktadır. Ayrıca, farklı araştırmalar arasında sonuçların doğrudan karşılaştırılmasına olanak tanımakta ve diğer ölçeklere uygulanabilecek kadar esnek bir yapı sunmaktadır.

Anahtar Kelimeler

• Psikolojik sıkıntı
• K6
• Entropi
• Eşik değeri
• Kanada Toplum Sağlığı Araştırması (CCHS)

Use of an Entropy Measure to Dichotomize a Variable

Öz

Numerous cut-off points have been identified in the literature for the 6-item Kessler Psychological Distress Scale (K6) used in Canadian population-based surveys. The rationale for selecting a cut-off point is often absent or poorly documented. The purpose of this paper is to present a new approach to identifying the rationale for the selection using only the distribution of K6 scores. An entropy measure was computed initially from the distribution of observed scores in the 25 K6 categories and subsequently for all possible cut-off points (two categories). This exercise was done using Quebec data from four cycles (2005, 2007-2008, 2009-2010 and 2013-2014) of the Canadian Community Health Survey (CCHS). The cut-off point selected is the one that provides a similar amount of information to that found for all 25 categories. The cut-off point selected for the four cycles of the CCHS was 5/6. This method underscores the importance of determining a cut off point empirically rather than adopting one simply because it has been used in previous studies. It also allows for straightforward comparison of results across different surveys and remains flexible enough to be applied to other scales.

Anahtar Kelimeler

• Psychological distress
• K6
• entropy
• cut-off point (threshold)
• Canadian Community Health Survey (CCHS)

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