Fig. 6From: Structural validity of the Boston Carpal Tunnel Questionnaire and its short version, the 6-Item CTS symptoms scale: a Rasch analysis one year after surgeryDifferential item functioning favoring age in item 5 (“How long on average does an episode of pain last during the daytime?”) of BCTQ Symptom Severity Scale. Note in figure: ‘Some person location values … decrease minimum location’ and ‘Person location’Back to article page