I think one of the most interesting things about this article is what it says about interpreter training.  This observation from Marjory Bancroft, a respected interpreter trainer in the US:

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 A new study compares professional, untrained and ad hoc interpreters in pediatric emergency rooms. Physicians from across the country analyzed 57 encounters: 20 with professional interpreters, 27 with ad hoc interpreters (e.g., untrained bilingual staff, family or friends), and 10 with no interpreters.

 

The study found 1,884 interpreter errors! And 18% of them had potential clinical consequences. But the errors of professional interpreters had significantly fewer clinical consequences (12%) versus ad hoc (22%) or no interpreters (20%).

Perhaps the most striking conclusion is that the "median errors by professional interpreters with greater than or equal to 100 hours of training was significantly lower than for those with fewer than 100 hours of training." (2% versus 12%, and in every error category).

 

The study concludes: "These findings suggest that requiring at least 100 hours of training for interpreters might have a major impact on reducing interpreter errors and their consequences in health care while improving quality and patient safety."

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Would seem quite relevant to the controversy in the UK about qualifications of interpreters under the new contracting scheme.