Evidence-Based Practice / Unit 22 EBP 3187 short lesson, about 20 seconds
Sample Size Follows the Question
Captions available
The idea
How many participants are needed follows from the size of effect worth detecting, not from what is convenient to recruit.
In practice
A study powered to detect a difference large enough to change practice, not to whoever was available.
Where people slip
Unit 10 made this point for improvement projects: too few participants and a real effect goes undetected, which is a finding about the study.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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