Table 6 Reported construct validity of GAS in included studies
First author | Year | Drug study | N | Methods and results | Quality |
|---|---|---|---|---|---|
Cusick | 2006 | Yes | 41 | Correlations with COMP and GAS Likert scale were measured; no correlation higher than −0.25 or with a p-value lower than 0.05. | +/− No hypotheses |
De Beurs | 1993 | Yes | 40 | Correlations with agoraphobia, rating of treatment outcome by therapist, M-BAT, depression and somatic anxiety were measured; GAS has a high correlation with gain scores on agoraphobia (0.63), rating of treatment outcome by therapist (0.43), and M-BAT (0.57). GAS is moderately correlated with depression (0.32), and not significantly correlated with somatic anxiety. | +/− No hypotheses |
Fisher | 2002 | No | 149 | Correlations with improvements in walking, general health questionnaire, Oswesty Low Back Pain Disability Questionnaire, NRS and change stand-sit and change PAIRS were measured. There was a significant correlation between GAS and improvements for walking (0.47), between GAS and the general health questionnaire (0.25) and between GAS and the OLBPDQ (−0.31), with p <0.01 for all three. No significant correlations were found between GAS and the NRS and change stand-sit and change PAIRS. | +/− No hypotheses |
Gordon | 1999 | No | 53 | Correlations with standard scales of cognition (MMSE and Global Deterioration Scale), behavior (axis 8 of the brief cognitive rating scale), co-morbidity (cumulative illness rating scale), mobility and balance (hierarchical assessment of balance and mobility, HABAM), and functional capacity (Barthel Index); GAS did not correlate well with any of these measures (correlations varied from −0.22 to 0.17). | +/− No hypotheses |
Khan | 2008 | No | 24 | Correlation with Barthel Index, Functional Independent Measure and Clinical Global Impression was measured; only the correlation with CGI was significant (−0.77). Also, the difference between responders and non-responders was measured, and a significant difference was found (Z = −3.78, p <0.001). | +/− No hypotheses |
Palisano | 1993 | No | 21 | Correlations between GAS T-scores and Peabody Gross Motor Age equivalent change scores were measured; none of these correlations were significant. | +/− No hypotheses |
Rockwood | 1993 | No | 45 | Correlations with change scores of Barthel Index, Functional Independent Measure, Mini-Mental State Examination, Katz ADL Index, Physical Self-Maintenance Scale, and Spitzer Quality of Life Index were measured. Correlations varied from −0.87 to 0.84, but it is unclear if these correlations are significant. | +/− No hypotheses, correlations between change scores |
Rockwood | 1996 | Yes | 15 | A correlation with change scores is measured between GAS and Alzheimer’s Disease Assessment Scale-cognitive, Global Deterioration Scale, Clinical Global Impression, Mini-Mental State Examination, Physical Self Maintenance Scale, and the Instrumental Activities of Daily Living. Correlations varied from −0.85 to 0.74, but it is unclear if these correlations are significant. A T-test between the placebo and the intervention condition was also performed. The T-test showed no difference (p = 0.54). | +/− No hypotheses, correlations between change scores |
Rockwood | 1997 | No | 44 | Correlations with two measurement instruments were measured: Clinical Global Impression (r = 0.73) for change score and (r = 0.63) at discharge. | +/− No hypotheses |
Rockwood | 2002 | Yes | 108 | Correlations were measured between several goals within GAS and other measurement instruments. Mini-Mental State Examination and GAS cognition goals: r = 0.51. Alzheimer’s Disease Assessment Scale-cognitive and GAS cognition goals: r = −0.43. Physical Self Maintenance Scale and clinical function goals: r = −0.53. Patient-carer function goals and Physical Self Maintenance Scale: r = −0.47. Patient-carer function goals and Instrumental Activities of Daily Living: r = −0.44. | +/− No hypotheses |
Sheldon | 1998 | No | 82 | GAS was correlated with the ‘rated attainment’ scale: r = 0.71 (p <0.001). There was a correlation with autonomy (r = 0.21, p <0.01), later effort (r = 0.42, p <0.01) and autonomous reasons (r = 0.09, p <0.05). | +/− No hypotheses |
Steenbeek | 2011 | No | 23 | Correlation with Pediatric Evaluation of Disability Inventory Functional Status Score Mobility: r = 0.64 (p <0.01), correlation with PEDI Selfcare and social function was not significant. | +/− No hypotheses |
Stolee | 1999 | No | 173 | Change and follow-up scores of GAS were correlated with Barthel Index, Older Americans Resource Scale Instrumental Activities of Daily Living, Mini-Mental State Examination, Global Rating, Nottingham Health Profile. The correlations varied from −0.31 to 0.67. | +/− No hypotheses |
Turner-Stokes | 2009 | No | 164 | Correlations were measured between GAS and Functional Independent Measure and Functional Assessment Measure. Correlations with FIM + FAM scores were moderate: 0.36–0.43 for raw scores, 0.41–0.49 for GAS transformed FIM + FAM scores. | +/− No hypotheses |
Turner-Stokes | 2010 | Yes | 90 | Correlations were measured between GAS and a composite spasticity score (MAS), Global Benefit patient report, Global Benefit investigator report, Hospital Anxiety and Depression Scale anxiety and Hospital Anxiety and Depression Scale depression, Pain at rest, Pain on movement, Assessment of Quality of Life, Patient Disability Score, and Carer burden score. Significant correlations between GAS and MAS (0.35), Global benefit patient report (0.46) and Global benefit investigator-report (0.41) were reported. Other correlations were not significant. | +/− No hypotheses |
Turner-Stokes | 2013 | Yes | 456 | Correlations between GAS and ‘other measures of outcome, e.g. measures of spasticity, global benefit and other standardized measures’ were calculated. GAS correlated weakly with a reduction in total Modified Ashworth Scale at follow-up (Sp r = 0.28, p <0.0001) and with global assessment of benefit (r = 0.45, p <0.0001 for patient assessment, r = 0.38, p <0.0001 for investigator assessment). | +/− No hypotheses |
Woodward | 1978 | No | 279 | GAS scores correlate significantly with other outcome measures: r = 0.12 - 0.39; p <0.05 (in the paper, it is not clear what these other outcome measures are). There was also a difference between the highest and lowest T-score differences: the highest scorers had a mean pre-post score difference of 42.70 (SD = 6.87), the lowest scorers had a mean pre-post difference of 4.05 (SD = 5.78). | +/− No hypotheses |
Yip | 1998 | No | 143 | Correlations with the Standardized Mini-Mental State Examination, the modified Barthel Index, the Katz Index of ADL and the IADL subscale of the Older Americans Resources and Services Questionnaire were used to demonstrate the convergent construct validity of the standardized menu of GAS. Spearman correlations were calculated between GAS summary scores at discharge and change scores on the Barthel, Katz, OARS-IADL, and SMMSE. The correlations of the total GAS score with changes on the three measures of function were statistically significant but modest (r = 0.41 to 0.45); the correlation of GAS with the SMMSE change score was not significant (r = 0.11). | +/− Modest correlations |