Psychologists Love To Report “Marginally Significant” Results, According To A New Analysis 

  Figure 3 from Olsson-Collentine et al, 2019: “Percentage of p values (.05 < p ≤ .10) reported as marginally significant (solid lines) and percentage of articles containing at least one such p value (dashed lines) between 1985 and 2016 in different psychology disciplines” By Matthew Warren One of the greatest temptations for psychologists is to report “marginally significant” research results. When statistical tests spit out values that are tantalisingly close to reaching significance, many just can’t help themselves.  Now a study in Psychological Science has shown just how widespread this practice is. Anton Olsson-Collentine and colleagues from Tilburg University analysed three decades of psychology papers and found that a whopping 40 per cent of p-values between 0.05 and 0.1 – i.e. those not significant according to conventional thresholds – were described by experimenters as “marginally significant”.  Psychologists use p-values to gauge whether a result is statistically significant. The p-value provides an estimate of the likelihood of the current results (and others more extreme) being obtained if the “null hypothesis” were true. (The null hypothesis is that there is no effect, or no difference between the groups being studied). At a certain threshold – usually when p is less than 0.05 – psychologists dismiss the null hypothesis and infer that their result probably represents a true effect. But sometimes researchers...
Source: BPS RESEARCH DIGEST - Category: Psychiatry & Psychology Authors: Tags: Methods Source Type: blogs