Early on, researchers came up with a standard description to bring some uniformity in assessment & proposed treatments.
The rule of 3's describes crying
for at least 3 hrs/day;3days/wk in the first 3 months of life. It implys crying when no physical need (feeding
) & no medical illness (reflux
, ear infection
, uti) were detected of thorough evaluation. It often occurred more in the afternoons.