Attribute	Criteria	Evaluation – US version	Evaluation – UK version
Conceptual and measurement model	The rationale for and description of the concept and the populations that the measure is intended to assess
	Clinical content and design	• A global measure of disability, designed primarily for use in patients with acquired brain injury. • FIM + FAM is a 30-item ordinal scale which extends the scope of the 18-item FIM, by adding 12 items primarily addressing psychosocial and cognitive aspects of function (which are often the principal factors limiting independent function in this group) [1]. • Items are scored on a seven-point scale ranging from 1 (total dependence) to 7 (complete independence). • Persons are rated by a multidisciplinary team of clinicians on the basis of observed performance not potential or capability, except for “Employability” which is rated on the basis of presumed capability.	• The UK version retains the same overall structure as the US version – 12 FAM items added to the 18 FIM items are scored on the seven-point scale structure, and rated similarly by a multidisciplinary team on the basis of observed performance [2]. • Intended for a similar group of patients, the UK version was designed by a multicentre Development Group, in collaboration with the FAM originators, to address the subjective nature of some of the items. Ten “troublesome” items were identified and adjusted [2]. • The FIM items remain consistent across the two versions. • Item level definitions differ slightly for the UK FAM items (see “Content” below) • A five-item module addressing extended activity of daily living (EADL) was also developed [3].
	Dimensionality	Data from two studies of patients with TBI: n = 60 [4], n = 965 [5]; and one of stroke patients n = 376 [6]: • Two distinct principal components representing Motor and Cognitive functioning [5]. • Three Rasch studies reported a number of misfitting items for full 30 items and for Motor and Cognitive subscales analysed separately. Indicates neither the full scale nor two subscales are entirely unidimensional [4–6]	Data from present study (n = 459) mixed neuro-rehabilitation inpatients: •  A strong principal component with all 35 items loading >0.55 on it. On rotation clear two-factor (Motor and Cognitive functioning) and four-factor solutions (Physical, Psychosocial, Communication and EADL) •  Mokken scaling H coefficient values of 0.64, 0.82 and 0.65 for Full Scale, Motor and Cognitive scales, respectively (H > 0.50 indicates a “strong” scale). •  H coefficients for four subscales Physical (H = 0.82), Psychosocial (H = 0.72), Communication (H = 0.72), EADL (H = 0.67).
Reliability	The degree to which the instrument is free from random error
	Internal consistency	Data from two studies of patients with TBI: n = 965 [5], n = 60 [4]; and one of mixed neuro-rehabilitation, n = 149 [7] • Cronbach’s α for full scale FIM + FAM = 0.96, Motor subscale = 0.99, Cognitive subscale = 0.98 [5,7] • Rasch person and item consistency high at 0.91 and 0.93, respectively [4]	Data from present study (n = 459) mixed neuro-rehabilitation inpatient sample: •  Cronbach’s α for Full Scale = 0.98, Motor subscale = 0.97 and Cognitive subscale = 0.96. •  Cronbach’s α for Physical (0.97), Psychosocial (0.95), Communication (0.92) and EADL (0.90) subscales •  Rasch analysis is currently underway – not yet published.
	Reproducibility	Data from two studies of patients with neurological injury – mainly ABI n = 30 [8]; and severe TBI n = 53 [9]: • Kappa ranged from 0.35 to 0.95 for 29/30 items [8] • ICCs ranged from good (0.60–0.74) to excellent (0.75–1.0) for 29/30 items [9]	Data from one vignette-based study of 28 clinician raters scoring individually and then in teams [2]: • Modest improvement in scoring accuracy of UK FIM + FAM in comparison with US version. Accuracy for individual item ratings improved from 75% (US) to 77% (UK) for and team accuracy from 84% to 86% [2] • Kappa ranged from 0.57 to 0.85 (for individual raters) and from 0.60 to 0.94 (for team ratings) across the 30 items. For EADL module, one vignette-based study: 50 vignettes and 12 clinician raters [3]: • Agreement with “gold standard scores” was high. Kappa ranging from 0.88 to 0.97 (individual ratings) and 0.93–1.0 (team ratings) [3]. • Inter-rater agreement ranged from Kappa 0.68 to 0.92 (individuals) and from 0.74 to 1.0 (teams). • Test–retest agreement Kappa values ranged from 0.92 to 1.0 (individuals) and 0.89–0.99 (teams) [3]:
Validity	The degree to which the instrument measures what it purports to measure
	Content	• 30 items tap different aspects of six important aspects of independence: self-care, bowel and bladder management, mobility, communication, psychosocial function and cognition	• Covers the same range of function as the FAM, with the exception of employability • Three items are significantly altered:  ○ “Use of Leisure time” replaces “Employability”;  ○ “Concentration” replaces “Attention”:  ○ “Safety Awareness” replaced “Safety Judgement”. • The five-item EADL module covered community-based activities: Meal preparation, Shopping, Laundry, Housework, Financial management [3]: • A sixth item (Work) has recently been added, but has not yet been fully tested.
	Criterion-related	Not testable – no accepted gold standard currently exists	As for the US version – not testable
	Concurrent	Data from five studies of patients with TBI: n = 48 [10], n = 332 [1], n = 612 [11], n = 167 [12], n = 54 [13]; acquired brain injury n = 52 [14]; and inpatient neuro-rehabilitation (n = 149) [7]. • Positive Spearman correlations between five FIM + FAM dimensions (comprehension, problem-solving, memory, orientation, attention) and seven standard neuropsychological tests – 29/40 correlations significant [14]. • Correlation with the OPCS (rho 0.82) [13] • Correlations with the DRS were FIM + FAM motor 0.68, FIM + FAM cognitive 0.75 [1] • FAM employment item correlated −0.86 and −0.96 with DRS level of function and DRS employability items, respectively [10] • FAM items displayed modest advantage over the FIM in predicting employment and community integration at 24 months post-TBI [12]. • High correlations between FIM, FIM + FAM Total, BI, FIM motor, FIM Cognitive, FIM + FAM Motor, FIM + FAM Cognitive – Pearson’s r = 0.96–0.99 [7] • Direction, magnitude and pattern of FIM + FAM correlations with six measures of similar and different constructs were as predicted supporting its convergent and discriminant validity	Data from one study of patients with acquired brain injuries (all causes) n = 164 [15]; and a mixed neuro-rehabilitation inpatient sample, n = 569 [16]. • Strong positive correlations between the FIM + FAM and the Barthel Index (rho = 0.84); moderate correlation (rho = 0.38) with personal goal attaiment scores [15] Strong positive correlation between UK FIM + FAM Motor scores and nursing dependency (NPDS) (rho 0.82–0.85) and between UK FIM + FAM Cognitive scores and NPDS Cognitive items (rho 0.76–0.77) [16]
Responsiveness	Ability to detect change over time where real changes occur
	Change: admission to discharge	Data from two studies of patients with TBI n = 94 [17] and n = 105 [18]; and one inpatient neuro-rehabilitation, n = 149 [7]. • Standardised response means (n = 139) for FIM and FIM + FAM were 0.48 and 0.42, respectively [7]. • Difference between Outreach (n = 48) and Information (n = 46) groups on change scores not significant for total score and all five subscales due to ceiling effects at intake [17]. • Paired t tests showed only two items (bowel management and bladder management) did not show significant improvement (n = 105). Clinically meaningful improvements detected by 20/30 items in ≥60% of patients. • FIM + FAM Motor score below the ceiling predicted referral for on-going therapy services with a sensitivity of 0.88 and specificity of 0.65 [18].	Data from one study of n = 65 neuro-rehabilitation outpatients [19]; and n = 164 inpatients with acquired brain injury [15]; in addition to data from this study (n = 459) • Neuro-rehabilitation outpatient programme. Mean admission–discharge change scores for Motor (12.0), Cognitive (7.3) and FIM + FAM total score (19.3) all clinically significant [19]. • Neuro-rehabilitation inpatient programme: Median admission–discharge change scores for Motor, Cognitive and FIM + FAM total score all clinically significant [15]. Data from this study confirm that significant changes were seen during inpatient rehabilitation across both FIM + FAM motor and cognitive domains (effect size 1.24 and 1.05, respectively) and across the four subscales (Effect sizes 0.86–1.29)
Floor/Ceiling effects	No. respondents with highest or lowest possible score	Data from five community-based TBI programmes (total N = 919) and one inpatient stroke study (n = 376) [6]: • Ceiling effects reported for community resident TBI survivors [4,10,11,17,18] and inpatient stroke rehabilitation [6]	Data from one neuro-rehabilitation outpatient study, n = 65 [19]: • Ceiling effects on individual items at the start of programme ranged from 4.6% to 90.8% and at discharge from 18.5% to 93.8% [19]
Interpretability	The degree to which easily understood meaning can be assigned to the quantitative scores
	Clinical meaning	• FIM + FAM provides two scores, one for motor independence and one for cognitive/behavioural independence, both of which are readily understood by clinicians • The cognitive items are noted to be more subjective and less “imageable” than the motor items, and so harder to rate reliably [20]	• As for the US version, the UK FIM + FAM divides into Motor and Cognitive domains. • The UK FIM + FAM software generates a “FAM-splat” providing an “at-a-glance” summary of change in the individual items of the FIM + FAM [21]
Burden	The time, effort or other demands of administering the instrument
	Time to administer	• Approximately 35 min	• Approximately 30 min
Alternative modes of administration		• Manual includes item level definitions and decision trees as for the FIM	• Manual includes item level definitions and decision trees as for the FIM
Cultural and language adaptations		• UK FIM + FAM [2] • German adaptation and translation [22]. ICCs for single FAM items ranged from 0.08 to 0.87 for inter-rater and from 0.50 to 0.99 for intra-rater reliability.	• Brazilian version [23] in Brazilian Portuguese. Intra-rater ICCs for 12 FAM items ranged from 0.60 to 0.94. ICCs for inter-rater reliability ranged from 0.51 to 0.90 across 12 items.

Data from this study are given in bold.

BI, Barthel Index; FIM, Functional Independence Measure; FAM, Functional Assessment Measure; FIM + FAM, Functional Independence Measure plus Functional Assessment Measure; ICC, Intra-Class Correlation.