In court practice, the MCA criterion “to use or weigh” was most frequently linked to the ability “to appreciate” and its subcategories: e.g. “He felt that [P] lacked insight into his cognitive and emotional problems; combined with his suspiciousness of the motives of others this constituted (in his view) an inability to weigh some care decisions in the balance,” as well as “reasoning” ability, for example ability to balance pros and cons: “She was not able to weigh up the positives and negatives of living in a particular environment.” It was also linked to less frequently occurring rationales such as “ability to imagine or abstract,” “ability to value or care,” “to think through decisions non-impulsively” and “to give coherent reasons.”
The ability to use or weigh was also linked to abilities in a hierarchical fashion, such as citation of an “upstream” inability to grasp information leading to inability to weigh, e.g. “With regard to weighing in the balance, this is, of course, hampered by the fact that he did not understand all the relevant information and that he therefore put too much weight on the factors that he did understand. For example, with decisions about residence he put too much weight on the basic physical characteristics and did not consider location or financial aspects sufficiently…” In this case the failure to use or weigh the relevant information is secondary to the fact that P fails to understand: in other words, to state in such cases that P fails to use or weigh is true but superfluous.
Recommendation – the “use or weigh” criterion occupies a large conceptual space. Whenever Use or Weigh is applied, capacity assessors should be sure to specify their rationale(s). This should lead to more transparent and reliable judgments and communications. See here for further discussion.