Validation of the "SmoCess-GP" instrument - a short patient questionnaire for assessing the smoking cessation activities of general practitioners: a cross-sectional study.
BACKGROUND
We developed an instrument assessing the extent of smoking cessation activities by general practitioners (GPs) within the Cologne Smoking Study (CoSmoS). The objective of the present study was to examine further psychometric quality of the "SmoCess-GP" instrument (Smoking Cessation by General Practitioners).


METHODS
127 current smokers who had participated in the Cologne Smoking Study (CoSmoS) were included in our analyses. Confirmatory factor analysis (CFA) was conducted to examine the model fit and to retest the single-factor structure of the instrument using the Mplus software. Further construct validity was tested with bivariate analysis using an instrument which measures patients' trust in physicians.


RESULTS
CFA supported the unidimensional structure of the instrument. The factor loadings exceed the threshold of > or = 0.50. All indicator reliabilities were higher than 0.30. The composite reliability was 0.86 and the average variance extracted (AVE) resulted in a value of 0.50. The calculation of global fit indices identified a CFI value of 1.00 and for TLI a value of 1.02. The root mean square error of approximation (RMSEA) indicates that 0% of the information is not accounted for by the model. The chi-square value was chi2df = 6 = 4.63 (p = 0.59). Analysis of discriminant validity resulted in a non-significant correlation of r = 0.092 (p = 0.350).


CONCLUSIONS
Results indicate preliminary evidence for the construct validity of the "SmoCess-GP" instrument which therefore appears to be a promising tool for analyzing the extent of smoking cessation advice offered by GPs from the patients' perspective. Future research should examine the psychometric properties in a population based sample, further improvements of the instrument and should apply other methods of validation.
Jung
Julia
J
Institute for Medical Sociology, Health Services Research and Rehabilitation Science (IMVR), Faculty of Human Sciences and Medical Faculty, University of Cologne & Centre for Health Services Research Cologne (ZVFK), Eupener Strasse 129, Cologne 50933, Germany. julia.jung@uk-koeln.de
Neumann
Melanie
M
Wirtz
Markus
M
Ernstmann
Nicole
N
Staratschek-Jox
Andrea
A
Wolf
Jürgen
J
Pfaff
Holger
H
D000328:Adult; D001291:Attitude of Health Personnel; D001294:Attitude to Health; D003430:Cross-Sectional Studies; D005163:Factor Analysis, Statistical; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D010817:Physician-Patient Relations; D010821:Physicians, Family / Q000523:psychology* / Q000706:statistics & numerical data; D011594:Psychometrics; D015203:Reproducibility of Results; D012907:Smoking / Q000523:psychology*; D016540:Smoking Cessation / Q000379:methods*; D000074606:Smoking Prevention; D011795:Surveys and Questionnaires / Q000592:standards*; D016896:Treatment Outcome; D035502:Trust