I notice in the zooms that the boxes that aren't correctly identified as being filled in have the value .000 next to them (for the most part). They are definitely filled in, however. No question about it.

Can you post a screenshot of a zooms window for a problematic scan?

Hi Alexis,

I seem to have been able to correct the problem by deleting and then re-importing the scans (pressing the automatic button). Not sure why that made a difference, but it did. I still get the sensitity column mostly in red, but for the most part the scans are correct.

Screen shot attached.

Were your exams printed or photocopied?

In my experience, small ovals work fine when printed, but can be problematic when photocopied because the process of photocopying
introduces slight distortions in the page size and proportions. You can often see when you superimpose the original and the photocopy that one might have slightly longer diagonal between page markers.

Normally it is not a problem, especially if you tweak the 'measured box proportion setting' to be a bit lower than default, say 0.65. However, with very small ovals, those small distortions are significant enough to cause some checked ovals to be unrecognized (about 2-3% in my experiments).

It is easy to get around this by simply increasing the size of ovals (this doesn't change the layout of the answer sheet).