PDF with chisq fails with unclear error message due to extraction issue (improve message / use pdftools?) about statcheck HOT 1 OPEN

In a larger set of files, this issue occurred another 8 times (e.g., 10.1016/j.jbusres.2018.11.029 and 10.1002/smj.2976) - so it is reasonably common and resolves by using pdftools. Another issue that occurred is that xpdf inserts As into two tests in the attached PDF, which are then no longer found.
10.1016--j.obhdp.2013.04.003.pdf

However, pdftools failed to extract some tests (without causing errors) due to problems in reading multi-column layouts. Another tool that I tried (pdfminer.six) resolves that, but also fails with some chisq ... so for now, I would no longer recommend a change in the default PDF engine, but clearer error messages. Also, it might be worth recommending that users re-OCR PDFs that fail (or, if striving for completeness, all). For instance, statcheck does not find results in the following file due to issues with the =, but works after running ocrmypdf --force-ocr

10.1002--job.220.pdf

from statcheck.