What this highlights strongly is that multiple choice (which I understand is still the mainstay of the US examination system) is a terrible way to assess compet

What this highlights strongly is that multiple choice (which I understand is still the mainstay of the US examination system) is a terrible way to assess competence in a subject. Its siren call is very strong however because of the convenience of automatic marking. Maybe with improvements in technology we will see moves away from it; eg my kids do all their Maths homework via a website that requires answers to be typed in, which although not ideal (it can't see the working-out process) is obviously better than multiple choice, and it seems to have some sensible leniency in its interpretation of input.