Landgraf, J.M.

health scale children study sample score child population quality questionnaire itqol parent condition hrqol symptom effect family asthma-like symptoms measure population sample difference month infant subgroup reliability result paper internet table disease itqol scales generation r study illness child health questionnaire behavior chq-pf impact development signi netherland correlation asthma-like reference activity landgraf validity rotterdam patient chq-cf subgroups effect sizes problem characteristic growth mother change health conditions itqol scale scores administration journal version status temperament complaint life research generation school number life questionnaire summary 0.00 asthma health perceptions test –retest reliability chq-pf 28 center rotterdam group research association fi rst year