The development and assessment of a Quality of Life measure (CASP-19) in the context of research on ageing Dick Wiggins Department of Quantitative Social Science The Institute of Education The University of London CCSR Seminar University of Manchester, 4 th December 2007

Some history………….. CASP-19 is a theory based Quality of Life Measure developed under the UKs Economic and Social Research Councils Growing Older Programme ( ) Original Team: David Blane Paul Higgs Martin Hyde Dick Wiggins

Followed by: Quality of Life and Resilience in Early Old Age David Blane, Dick Wiggins, Scott Montgomery, Gopal Netuveli and Zoë Hildon ESRCs Priority Network on Human Capability and Resilience Network Coordinator: Mel Bartley, UCL

Research Settings for evaluation: The Boyd-Orr sample The English Longitudinal Study of Ageing (ELSA) The British Household Panel Survey (BHPS, Wave 11)

The Boyd-Orr sample Boyd-Orr Study; childhood diet and health Gunnell at al, Public Health 110, Life Grid Interview: retrospective data, Physiological and anthropmorphic measures Berney and Blane, Social Science and Medicine, 45, Postal Questionnaire Hyde et al., Aging and Mental Health, 2003 Boyd-Orr 2000

Some theory…………. Needs Satisfaction and Quality of Life Maslow, A.H. (1963) Toward a psychology of being Giddens, A. (1990). The consequences of Modernity Doyal, L. and Gough, I. (1991). A theory of human need Laslett, P. (1996). A fresh map of life

Concepts and indicators…… Quality of life

Concepts and indicators…… Quality of life Control Autonomy Self- realisation Pleasure

Concepts and indicators…… Quality of life Control Autonomy Self- realisation Pleasure

Concepts and indicators…… Quality of life Control Autonomy Self- realisation Pleasure Item 1 Item 2 Item 3 Item 4 Item 19

Concepts and indicators…… Quality of life Control Autonomy Self- realisation Pleasure Item 1 Item 2 Item 3 Item 4 Item 19

CONTROL My age prevents me from doing the things I would like to do I feel that what happens to me is out of my control I feel free to plan for the future I feel left out of things Alpha = 0.6

AUTONOMY I can do the things I want to do Family responsibilities prevent me from doing what I want to do I feel that I can please myself what I do My health stops me from doing the things I want to do Shortage of money stops me from doing the things I want to do Alpha = 0.6

Self-realisation I feel full of energy these days I choose to do things that I have never done before I fell satisfied with the way my life has turned out I feel that life is full of opportunities I feel that the future looks good for me Alpha = 0.8

Pleasure I look forward to each day I feel that my life has meaning I enjoy the things that I do I enjoy being in the company of others On balance, I look back on my life with a sense of happiness Alpha = 0.8

The scale found a niche….. Take up in ….. English Longitudinal Study of Ageing (ELSA) British Household Panel Survey (BHPS) Retirement Module Wave 11 Study of Health, Alcohol and Psychosocial factors in Eastern Europe (HAPPIE) An evaluation of Camdens Quality of Life Strategy for older citizens NCDS 2008 as they reach 50 years of age

Fuelling motivation so much is known about the variations which can be produced, and so little is known about which variation is most nearly correct, McNemar, Confirmatory factor analysis of the GHQ- 12: can I see that again? Campbell et al., Australian and New Zealand J of Psychiatry 2003; 37:

Some reflection and acknowledgement Ed Diener

Some reflection and acknowledgement Ed Diener Subjective Measures of Well-Being

Three possibly four pillars Self-report: perception is reality Positive and negative aspects of central concept: life domains are important The need for global assessment Theory distinguishes the usefulness of your measure

Measurement Models

Evaluation Strategy Fit three measurement models for complete data across three research settings using multigroup analysis in AMOS. Reflect, assess three measurement models for two national data sets taking account of measurement level and item non-response in Mplus.

CASP19 First order model

CASP19 second order model

Assessing goodness of fit Aim: to reproduce covariance/correlation matrix Criteria are typically functions of discrepancy

A selection of criteria 2 or CMIN represents the discrepancy between the sample covariance matrix and the fitted matrix Tends to be substantial when model does not fit or sample large Resulting in a plethora of indexes which take a more pragmatic approach to the evaluation process (Byrne,2001). Key reference: Bollen, K.A. and Long, J.S. Testing structural equation models. Newbury Park, CA: SAGE, 1993

2 / DF the first on the block Other adjuncts to 2 include: Goodness of fit index GFI A measure of the relative amount of variance and covariance explained Adjusted GFI Adjusts for degrees of freedom Both GFI and AGFI range between 0 and 1 (near 1 good)

Root Mean Square Error of Approximation RMSEA A measure of discrepancy per degree of freedom Values up to.08 indicate a reasonable fit RMSEA > 0.10 poor < 0.05 good

Model fit indices continued Tucker Lewis Index (TLI) { (χ 2 0 /df 0 ) - (χ 2 1 /df 1 ) } / { (χ 2 0 /df 0 ) -1 } Comparative Fit Index (CFI) { (χ 2 0 /df 0 ) - (χ 2 1 /df 1 ) } / (χ 2 0 – df 0 ) These measures are calculated in relation to the null model where all parameters are set to zero. For both, >0.90 good, >0.95 > very good.

Moving on….. Multigroup analysis Testing the invariance of the factorial measurement and structure across sample settings Involves comparing an unconstrained model for the samples as a whole with a constrained model across the three groups.

Modelling Strategy…………. separate analyses for three settings

Modelling Strategy…………. separate analyses for three settings Complete data only BO-2000 : 198 ELSA : 9910 BHPS : 6471 All aged 50 +

Modelling Strategy…………. separate analyses for three settings Boyd-Orr 2000 ELSA BHPS Wave 11 combined MULTIGROUP analysis

Software………. AMOS James L. Arbuckle AMOS Graphics

1 st order model with standardised regression weights

1 st order model (errors correlated) with standardised regression weights

Model fit indices for 1 st order model Data setCMIN/dfGFIAGFIRMSEA Boyd Orr BHPS ELSA Multi- group

Model fit indices for 1 st order model with errors correlated Data setCMIN/dfGFIAGFIRMSEA Boyd Orr BHPS ELSA Multi- group

CASP19 second order model

2 nd order model with standardised regression weights

2 nd order model (errors correlated) with standardised regression weights

Model fit indices for 2 nd order model Data setCMIN/dfGFIAGFIRMSEA Boyd Orr BHPS ELSA Multi- group

Model fit indices for 2 nd order model with errors correlated Data setCMIN/dfGFIAGFIRMSEA Boyd Orr BHPS ELSA Multi- group

The search for empirical stability Structures that dont let you down…..

CASP12 second order model

Rank Order Correlations for Boyd-Orr 2000 CASP

Dilemma Compromise or re-examine theory ??

CONTROL My age prevents me from doing the things I would like to do I feel that what happens to me is out of my control I feel free to plan for the future I feel left out of things Alpha = 0.6, remains at 0.6

AUTONOMY I can do the things I want to do Family responsibilities prevent me from doing what I want to do I feel that I can please myself what I do My health stops me from doing the things I want to do Shortage of money stops me from doing the things I want to do Alpha = 0.6, remains at 0.6

Self-realisation I feel full of energy these days I choose to do things that I have never done before I fell satisfied with the way my life has turned out I feel that life is full of opportunities I feel that the future looks good for me Alpha = 0.8, remains at 0.8

Pleasure I look forward to each day I feel that my life has meaning I enjoy the things that I do I enjoy being in the company of others On balance, I look back on my life with a sense of happiness Alpha = 0.8, now 0.7

Pairs of items with correlated error terms from CASP-19 Age inhibits activities (C) with My health stops me… (A) Feel free to plan for the future… (C) with Life is full of… (SR) I can do the things… (A) with I enjoy the things.. ((P) Family responsibilities…(A) with I feel full of energy..(SR)

My health stops me.. (A) with I feel full of energy…(SR) I enjoy being in the company..(P) with I feel full of.. (SR) On balance I look back… (P) with I feel satisfied about.. (SR) I feel that I can please… (A) with My health stops me.. (A) My health stops me… (A) with Life is full of opportunities (SR)

Now turning to Mplus to address Measurement properties Item non-response Early results based on Version 3.01 Version 4.0 on order (

Data setPercentage of complete cases Degree of missingness BHPS ELSA

Full Information Maximum Likelihood (FIML) for missing data Imputation model is embedded in analytical model Schafer, J.L. and Graham, J. (2002). Missing data: our view of the state of the art. Psychological Methods, 7, Muthén, B., Kaplan, D., & Hollis, M. (1987). On structural equation modelling with data that are not completely missing at random. Psychometrika, 42,

Goodness of fit indices :ELSA ModelCFIRMSEATLI Single First Order Second order

Goodness of fit indices :BHPS ModelCFIRMSEATLI Single First Order Second order

Correlations of ELSA and BHPS factor loadings: ModelProduct moment correlation Single factor0.98 First order0.98 Second order0.98

Internal Consistency analysis: bottom-up Cronbachs Alpha Domain/ DATA ControlAutonomySelf- realisation Pleasure ELSA BHPS

Refinement Compromised with a 12-item version by a process of item elimination Combining domains for control and autonomy (alpha =0.67) Global index still attains an alpha of 0.87

The next steps and the need for more theory Further scale refinement –Use of modification indices as for AMOS analysis? Sample weights: in BHPS individual weights compensate for differences in final stage of selection and a non response adjustment Multi-group analysis -issue differential weights by group ? Allow for clustering use multilevel analysis

Forthcoming publication The evaluation of a self-enumerated scale of quality of life (CASP-19) in the context of research on ageing: a combination of exploratory and confirmatory approaches. Wiggins, Netuveli, Hyde, Higgs and Blane (2008). Social Indicators Research