This paper on our study of how doctors (mis)conceptualised p-values was published in the October 2018 issue Australian Journal of General Practice. (PDF)
Tam CWM, Khan A, Knight A, Rhee J, McLean K, Price K. How doctors conceptualise P values: a mixed methods study. Australian Journal of General Practice 2018 09/26;47:705-10.
Abstract
Background and objectives
Researchers and clinicians have been criticised for frequently misinterpreting and misusing P values. This study sought to understand how general practitioners (GPs) in Australia and New Zealand conceptualise P values presented in the manner typically encountered in a medical publication.
Methods
This mixed-methods study used quantitative and qualitative questions embedded in an online questionnaire and delivered through an Australian and New Zealand GP-specific Facebook group in 2017. It included questions that elaborated on the participant’s conceptualisation of ‘P = 0.05’ within a scenario and tested their P value interpretation ability and confidence.
Results
There were 247 participants who completed the questionnaire. Participant conceptualisations of P values were described using six thematic categories. The most common (and erroneous) conceptualisation was that P values numerically indicated a ‘real-world probability’. No demographic factor, including research experience, seemed associated with better interpretation ability. A confidence–ability gap was detected.
Discussion
P value misunderstanding is pervasive and might be influenced by a few central misconceptions. Statistics education for clinicians should explicitly address the most common misconceptions.
