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Sample Characteristics

The core standardisation sample consisted of 333 people (172 females, 161 males) ranging in age from 16 to 89, with a mean age of 44.3 years (SD = 18.17). The extent to which the standardisation sample matched the general adult population was examined using data from the UK 2001 census. Chi-square goodness-of-fit tests revealed that the actual sample distribution of age, education, gender and ethnicity did not differ significantly from the expected census figures.

In addition to the core standardisation sample, a mixed clinical sample of participants with cerebral pathology was recruited (n=75). All clinical participants completed both versions of the RBMT-3. In order to examine possible score differences on the RBMT-3 for different types of clinical disorder, this sample contained participants from each of the following clinical categories:
• Traumatic Brain Injury
• Stroke
• Encephalitis
• Progressive conditions such as Alzheimer’s Disease

Generating norms for the RBMT-3

Raw scores on the 14 RBMT-3 subtests are converted subtest scaled scores with a mean of 10 and a standard deviation of 3. Percentile ranks for scaled scores are also provided. Subtests take into account an individual’s age and data is reported for the following age bands:

16-24 years of age
25-34 years of age
35-44 years of age
45-54 years of age
55-64 years of age
65-74 years of age
75-89 years of age

In addition to providing scaled scores for the RBMT-3 subtests, a General Memory Index (GMI), representing overall memory performance, was also created. This index is standardised to have a mean of 100 and a standard deviation of 15. GMI scores are calculated by summing the scaled scores on the RBMT-3 subtests and then converting this sum to a GMI using the appropriate conversion table. These conversion tables also report the confidence intervals and percentile ranks for each GMI.

Alternate form reliability for each subtest was measured for Version 1 and Version 2 of the sample with the normative and clinical sample combined. Reliability coefficients ranged from 0.57 to 0.86. The reliability coefficient of the GMI was 0.87 for both Versions 1 and 2.

With the exception of the Messages Delayed subtest the inter-scorer reliability for the RBMT-3 subtests were 0.9 or higher, indicating a high level of agreement between scorers. The lower level of agreement on the Messages Delayed subtest was attributable to only two of the 18 pairs who completed the inter-scorer study and is thought to be due to two examinees whose results were particularly difficult to score on this subtest.

The RBMT-3 demonstrated good construct and ecological validity (as supported by performance against the Prospective and Retrospective Memory Questionnaire; Smith et al., 2000). In assessing the clinical validity of the tool the results provided strong evidence of the sensitivity of the RBMT-3 to memory problems.

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