[The G-Score - a Short Questionnaire for the Measurement of Subjective Physical Health].

AIM: The measurement of subjective physical health is important in clinical settings as well as for research purposes. In the present paper, the psychometric properties of the G-Score, a 4 item screening questionnaire for the self-assessment of one's physical health, is explored.

METHODS: The Objectivity, validity and reliability were estimated. Moreover, an item analysis and a suitable cut-off-value for the differentiation between healthy and presumably ill subjects were conducted. Data from the Saxony Longitudinal Study ("Sächsische Längsschnittstudie") 1998-2013 were analysed (N=324-417 healthy individuals).

RESULTS: The objectivity of the G-Score is estimated as very good. As a cut off for the differentiation between healthy and presumably ill subjects, a G-Score of 4 is suggested. The content validity is slightly lacking. Correlations with associated and non-associated constructs hint an interaction of physical with psychological discomfort. A good predictive validity of the instrument is assessed. Reliability estimates show acceptably good results. This indicates a high sensitivity for changes in the measured construct.

CONCLUSION: Putting all results into consideration, a use of the G-Score as a screening questionnaire in research is recommended. However, more psychometric investigations with representative samples and objective comparative data should be carried out.