Precision (of a study)

What It Is

Related to study power, which is the probability that a statistical test will reject the null hypothesis (usually, “groups are not different”) if in fact the null hypothesis is wrong.  Indicates the range of possible results which could occur with repeated, identical studies.

Why It’s Important

Studies with high precision indicate that their results are reliable, i.e. would be repeated in similar circumstances.  This increases their usefulness in factoring them into clinical decision making. Caveat:  a study can have high precision but be poorly designed and provide reliable, but wrong, evidence.