Table 1.
Summary of included assessment tools (presented by year of publication)
| Assessment tool | Type | Abilities assessed | Administration time | Population | Validity | Internal consistency | Interrater reliability |
|---|---|---|---|---|---|---|---|
| Two-part consent form76 | Self-administered questionnaire and semistructured interview | Understanding | Not reported | Psychiatric patients | Good agreement with expert judges; correlated with age, education, occupational level, and mental status | Test–retest r=0.70–0.76; | Interrater r=0.94–0.96; Kappa =0.44–0.83 |
| CIS77 | 15-item structured interview | Understanding, appreciation, reasoning and choice (four subscale scores) | Not reported | Patients undergoing electroconvulsive therapy | Correlation with the physician’s judgment Pearson’s r=0.43–0.98 | Cronbach’s α=0.96 | Interrater reliability was 0.95 for CIS total score excellent |
| Deaconess informed consent comprehension test78 | Structured interview Requires training | Understanding | <10 minutes | Trials evaluating anti-infective agents | Correlated with Wechsler Adult Intelligence Scale – Revised (r=0.44), reading (r=0.38), and education (r=0.33) | Test–retest reliability intraclass r=0.79 | Interrater r=0.84 |
| ESC38 | Five-item questionnaire delivered after information about the study, but before the formal consent process Requires training | Understanding | 5–10 minutes | Schizophrenia and HIV Also tested in 346 nursing home residents42 | Correlated with MacCAT-CR Validity measured by item mapping with fit from 0.81 to 1.0942 | Not reported | Interrater reliability (r=0.81)42 |
| ICS79 | 36-item questionnaire Requires training | Choice, understanding, appreciation, and reasoning | Not reported | Schizophrenia | Correlated with the Brief Psychiatric Rating Scale r=−0.17 to −0.33 | Not reported | Not reported |
| Vignette methods described by Schmand et al (1999)36 | Vignettes, structured interview | Understanding, reasoning, and expression of a choice | 30–45 minutes | Older adults with or without dementia | Poor agreement with physician’s judgment of competency; correlated with severity of dementia Kappa =0.31 | Cronbach’s α=0.69 | Not reported |
| CAT80 | Semistructured interview Requires training | Choice, understanding, appreciation, and reasoning | Not reported | Developed in primary care setting on a small patient sample | Good agreement with independent psychiatric assessment Kappa =0.77–1.00 | Not reported | Not reported |
| MacCAT-CR37 | 21-item structured interview | Appreciation, understanding, reasoning, and choice (four subscale scores) | 15–20 minutes | Developed initially on patients with mental illnesses (depression, schizophrenia) but also evaluated in dementia (Alzheimer’s disease),44,47 cancer,81 HIV disease, diabetes, and control subjects | Correlations with Brief Psychiatric Rating Scale and MMSE; distinguishes between patients and control subjects Kappa >0.97 for each subscale81 | Poor test–retest correlations: Kendall’s Tau =−0.15 for reasoning, 0.26 for understanding, and 0.36 for appreciation82 | High interrater reliability (ICC: 0.78–0.98)44,47,83 Kappa =0.53–0.7984 |
| Quality of informed consent questionnaire85 | Self-administered 34-item questionnaire | Understanding (objective and subjective) | Mean completion time: 7.2 minutes (2.5–12.8) | Cancer patients | Consensus among independent experts: accuracy and comprehensiveness No correlation or agreement measure with expert panel conducted |
Test–retest ICC: 0.66 for objective understanding and 0.77 for subjective understanding | Not reported |
| CSA86 | 18-item structured interview (13 close-ended questions and five open-ended questions) Requires training | Appreciation | 10–20 minutes | Schizophrenia or related psychotic disorder and controls | Correlated with psychopathology and cognitive impairment | Cronbach’s α: 0.83–0.88 | Interrater percent agreement: 0.82–100 |
| Brief informed consent test, Buckles et al39 | 11-item questionnaire (yes/no questions) Requires training | Understanding | 5–10 minutes | Older patients with dementia | Correlated with Clinical Dementia Rating (Spearman r=−0.48) and MMSE (Pearson r=0.58) Not compared with other tests such as MacCAT-CR |
Internal consistency: Cronbach’s α=0.63 or 0.70 (with one item removed) | Not reported |
| Capacity-to-consent screen52 | 10-item questionnaire | Choice, understanding, appreciation, and reasoning | 20 minutes | Psychiatric populations | Tested on 68 patients and correlated to psychiatric evaluation but psychometric properties not given | Not reported | Not reported |
| UBACC questionnaire40 | 10-item questionnaire | Understanding, appreciation and reasoning | <5 minutes | Middle-aged and older outpatients with schizophrenia and healthy comparison subjects40 | Correlation with the MacCAT-CR scores Sensitivity 89% Specificity 100% |
Internal consistency: Cronbach’s α=0.77 | Interrater reliability: ICC 0.84–0.98 |
| OACCR41 | Four-item scale | Choice, understanding, appreciation, and reasoning | Brief, no time reported | Older patients in community and institutional settings | Validity evaluated in reference to the capacity to Consent Screen Score52 Pearson’s coefficient r=0.939 Sensitivity 99.2% Specificity 72.9% |
Cronbach’s α=0.85 | Item-total correlation: 0.59–0.76 |
Abbreviations: CAT, capacity assessment tool; CIS, Competency Interview Schedule; CSA, California Scale of Appreciation; ESC, evaluation to sign consent; ICC, intraclass correlation coefficient; ICS, Informed Consent Survey; MacCAT-CR, MacArthur Competence Assessment Tool for Clinical Research; MMSE, mini–mental state examination; OACCR, older adults’ capacity to consent to research; UBACC, University of California Brief Assessment of Capacity to Consent.