A new study conduucted by John B. Lee for the American Federation of Teachers concludes that liberal bias might come from a source other than liberal
attitudes.

Another theme [Lee] returns to over and over again is one of demonstrating…causal relationships. He notes that there are many explanations for political trends and demographics among the professoriate, so it is unfair to assume that a liberal tilt (assuming one exists) reflects bias. He notes, for example, that the studies do not explore whether there could be non-political explanations.

I’m dying to know? What does cause liberal bias, if not underlying attitudes?

Even if we grant that liberals might self-select to be members of academe, that condition doesn’t explain how something other than their attitudes creates bias in classroom experience, course material, etc.