Meditation retreat research, by the numbers

Hedge's g is a standardized effect size: it describes how far apart two sets of results are, measured in units of their spread, so findings from different studies can be pooled. Researchers often read values around 0.2 as small, around 0.5 as moderate and around 0.8 as large. The study's figures of 0.45 and 0.49 sit in the moderate range, which matches its own conclusion that traditional meditation retreats are moderately effective. The 95% confidence intervals, 0.35 to 0.54 and 0.36 to 0.61, show the likely range of the true effect. Neither interval reaches zero, and both p values are below 0.00001, which means the results are very unlikely to be chance alone.

The meta-analysis pooled many traditional retreats with different teachers, lengths and methods. It does not measure Andrew Keaveney's programs specifically, and this site makes no claim that his retreats produce any particular result. Effect sizes describe averages across groups, so individual experiences vary widely. A retreat is also not a medical treatment: if you are managing a health or mental health condition, keep your care team involved. What the research does support is the general idea behind going on retreat, that setting aside consecutive days for guided practice is worth taking seriously.