All 4 faces pain scales were found to be adequately supported by psychometric data .
When given a choice between faces scales , children preferred the WBFPRS .
Confounding of pain intensity with affect caused by use of smiling and crying anchor faces is a disadvantage of the WBFPRS .
: For clinical use , we found no grounds to switch from 1 faces scale to another when 1 of the scales is in use .
CONTEXT : Numerous faces scales have been developed for the measurement of  pain intensity in children .
It remains unclear whether any one of the faces scales is better for a particular purpose with regard to validity , reliability , feasibility , and preference .
OBJECTIVES : To summarize and systematic ally review faces pain scales most commonly used to obtain self-report of pain intensity in children for evaluation of reliability and validity and to compare the scales for preference and utility .
Children's ratings of the intensity and unpleasantness of post-operative pain using facial expression scales.
This study explored whether global unidimensional self-report pain scales based on facial expression help children separately estimate the sensory and affective magnitude of post-operative pain . Ninety paediatric elective surgery patients ( in two age groups : 5 - 9 and 10 - 15 years ) used each of four scales to estimate pain intensity and pain affect during the first 2 days after surgery . The four scales were :  Faces Pain Scale ( FPS ) , Facial Affective Scale ( FAS ) , and the Coloured Analogue Scale ( CAS )  ( one for intensity and one for unpleasantness ) . As hypothesised , ratings on the FPS correlated more highly with analogue scale ratings for intensity than for unpleasantness , whereas ratings on the FAS correlated more highly with those on the analogue scale for unpleasantness than for intensity . Factor analysis indicated that although all measures loaded on a single dimension of distress , there was an additional weaker factor corresponding to a unique contribution of the FAS . No systematic age effects were observed . It was concluded that the FPS and the FAS may partly measure different aspects of the postoperative pain experience in children , although shared instrument variance may obscure true estimates of covariation in ratings of intensity and affective magnitude . The clinical relevance of the present results remains to be determined
All 4 faces pain scales were found to be adequately supported by psychometric data .
When given a choice between faces scales , children preferred the WBFPRS .
Confounding of pain intensity with affect caused by use of smiling and crying anchor faces is a disadvantage of the WBFPRS .
: For clinical use , we found no grounds to switch from 1 faces scale to another when 1 of the scales is in use .
CONTEXT : Numerous faces scales have been developed for the measurement of  pain intensity in children .
It remains unclear whether any one of the faces scales is better for a particular purpose with regard to validity , reliability , feasibility , and preference .
OBJECTIVES : To summarize and systematic ally review faces pain scales most commonly used to obtain self-report of pain intensity in children for evaluation of reliability and validity and to compare the scales for preference and utility .