[From the article “Come Again”]: “The GRIM test, short for granularity-related inconsistency of means, is a simple way of checking whether the results of small studies of the sort beloved of psychologists (those with fewer than 100 participants) could be correct, even in principle. … “
To understand the GRIM test, consider an experiment in which participants were asked to assess something (someone else’s friendliness, say) on an integer scale of one to seven. The resulting paper says there were 49 participants and the mean of their assessments was 5.93. It might appear that multiplying these numbers should give an integer product—ie, a whole number—since the mean is the result of dividing one integer by another. If the product is not an integer (as in this case, where the answer is 290.57), something looks wrong.”
When the authors of the GRIM test took their simple test to analyse 71 papers in three leading psychology journals, they found that over half the papers failed the test. To read more, click here.