Reliability and validity of Life Satisfaction Index A in study on attempted suicide among rural residents

Objective To assess the reliability and validity of Life Satisfaction Index A(LSIA) in a case-control study on attempted suicide among rural residents.Methods A total of 407 attempted suicides happened from October 1,2009 to March 31,2011 were enrolled in the study.The control was matched with the same age(no more than 3 years),gender and residenctial place as the attempted suicide.The reliability and validity of LSIA was evaluated by calculating Cronbach's alpha coefficient,correlation coefficient,construct validity,criterion-related validity,and discriminant validity.Results The Cronbach α values were 0.828 and 0.734 in attempted suicides and living controls,respectively.The item-total correlation coefficients,if the item was deleted from the scale,ranged from 0.134 to 0.648(P<0.05) for the suicide group and 0.095 to 0.524(P<0.05) for the control group.Exploratory factor analysis was carried out and 5 factors were yielded in attempted suicide group,including zest to life,resolution and fortitude,congruence between desired and achieved goals,and self-assessment and mood,with a cumulative contribution rate of 52.89% of the total variance.And in the control group 6 factors were yielded,including zest to life,resolution and fortitude,congruence between desired and achieved goals,self-assessment,and mood and indifference,with a cumulative contribution rate of 51.45% of the total variance.The total scores of LSIA,Beck Hopelessness Scale(BHS),and Center for Epidemiologic Studies Depression Scale(CES-D) were 12.20±4.86,44.85±20.72,and 13.25±16.59,respectively.Criterion validity analysis demonstrated a negative correlation among the scores of LSIA and BHS,CES-D(r=-0.720,-0.715,P<0.001 for all).The total score of LSIA in the attempted suicides was 9.39±4.59,while the score of LSIA in the controls was 15.00±3.23,with a significant difference between the two groups(t=20.20,P<0.001).Conclusion The reliability,criterion validity and structural validity of Life Satisfaction Index A are acceptable in attempted suicide study.However,further research is needed to modify and improve some items.