Researchers studied 352 adults: 146 adults diagnosed with ADHD, 97 adults referred to the same adult ADHD clinic but not diagnosed, and 109 community volunteers. In each group, 94% identified as White.
The team compared how well two measures of executive function predicted problems at work: a self-rating scale about daily life and a set of lab tests. Work problems came from people's own job histories, ratings from employers and a clinician's rating of overall functioning.
Looked at apart from the lab tests and after allowing for IQ, the self-ratings predicted problems on all 11 work measures. They were especially strong at predicting the clinician's rating. The lab tests predicted some measures but explained much less. No test predicted the share of jobs a person had been fired from. Looked at together, the tests added useful information beyond the ratings for just 1 of the 11 measures.
Employer ratings existed for only 39 adults with ADHD, 25 clinic-referred adults and 50 volunteers, and those results could not be shown to be more than chance, which the authors put down to the small numbers.
Job histories were self-reported and may be affected by memory errors. Combining the clinic groups with community volunteers may have made the links look stronger, so the results may not apply to the general population.
The authors suggest that neither ratings nor tests should be used alone to measure executive function problems in clinical groups such as adults with ADHD.
The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Barkley, 2010: share of the differences in work measures explained by the self-ratings, after IQ, 5% to 22%.
- Barkley, 2010: share of the differences in the clinician rating (SOFAS) explained by the self-ratings, 63%.
- Barkley, 2010: share of the differences in the remaining work measures explained by the lab tests, after IQ, 1.6% to 18.6%.
- Barkley, 2010: share of the differences in the clinician rating (SOFAS) explained by the lab tests, after IQ, 21.2%.
- Barkley, 2010: extra share explained by the lab tests when the self-ratings went first, 2% to 27% (significant for only 1 of 11 measures).
- Barkley, 2010: extra share of the clinician rating (SOFAS) explained by the lab tests when the self-ratings went first, 2%.
- Barkley, 2010: share of employer-rated impairment explained by ratings and tests together, 40% (not significant).
- Barkley, 2010: share of employer-rated work performance explained by ratings and tests together, 46% (not significant). What the terms mean:
- Share of the differences explained (variance) How much of the spread in people's scores on one measure is accounted for by another. Higher means a stronger link.
- SOFAS A rating of a person's functioning made by a clinician.
- Significant Unlikely to be down to chance.
Source: Barkley R, Murphy K. Impairment in Occupational Functioning and Adult ADHD: The Predictive Utility of Executive Function (EF) Ratings Versus EF Tests. Archives of Clinical Neuropsychology (2010). doi:10.1093/arclin/acq014