Now this could start a fight

There is a paper forthcoming in the American Economic Journal titled "Partisan Grading" by two economists Talia Bar and Asaf Zussman. The abstract reads:

We study grading outcomes associated with professors in an elite university in the United States who were identified - using voter registration records from the county where the university is located - as either Republicans or Democrats. The evidence suggests that student grades are linked to the political orientation of professors: relative to their Democratic colleagues, Republican professors are associated with a less egalitarian distribution of grades and with lower grades awarded to Black students relative to Whites.

One thing I noted taking a very quick look at the papers was:

We were able to match 511 out of 1,169 professors, i.e. about 44 percent of the total. Of these professors, 27 (5.3 percent) are Republicans and 370 (76.3 percent) are Democrats. The rest either registered to vote for smaller parties or were unaffiliated with any party.

Only 5.3% of the professors stated they were Republicans with three quarters of the sample being Democrats. And what do we make of results based on 27 people?

As to the second result noted in the abstract, that Republicans give lower grades to Black students, Bar and Zussman write,

An obvious question that arises regarding the second finding is whether and to what extent Democratic professors “discriminate” in favor of Black students or Republican professors “discriminate” against them. At this stage we only note that in the absence of an appropriate benchmark for comparison, this question cannot be credibly answered;

One thing I would like to know is what effects on this result does the ethnicity of professor have? That is, Do Black Republican/Democratic professors grade in the same way as White Republican/Democratic professors? Another point Bar and Zussman make is that

Our analysis finds practically no association between professor political orientation and the relative grading outcomes of Hispanic and female students.

So, Why only “discrimination” for/against Black students?

Bar and Zussman’s results on the grading question show

The variance of grades is higher in courses taught by Republicans than in courses taught by Democrats. Moreover, in additional analysis we find that relative to their Democratic colleagues, Republican professors tend to assign more very low and very high grades: the share of the lowest grades (F, D-, D, D+, and C-) out of the total is 6.2 percent in courses taught by Republican professors and only 4.0 percent in courses taught by Democratic professors; the share of the highest grade (A+) out the total is 8.0 percent in courses taught by Republican professors and only 3.5 percent in courses taught by Democratic professors. Both differences are highly statistically significant. These suggestive results are consistent with our grading egalitarianism hypothesis.

A different illustration of the relationship between political identification and grading egalitarianism is contained in the chart above. The figure displays mean grades by student SAT score ranges in courses taught by Republican and Democratic professors. The observed pattern is consistent with the hypothesis that Republican professors are associated with a steeper slope of the grade-ability profile, i.e. with higher returns to student ability. (Emphasis added.)

One wonders about selection issues here. As Mark J. Perry says,

One conclusion here might be that highly motivated, high-achieving students should prefer classes from Republican professors because it's more likely they'll be rewarded with a really high grade (A or A+), and less motivated, lower-achieving students should prefer classes from Democratic professors, because it's less likely that they'll receive a really low grade.

The conclusion of the paper states,

We studied grading outcomes associated with professors in an elite university in the United States who were identified - using voter registration records from the county where the university is located - as either Republicans or Democrats. Assuming that Republicans are conservative and Democrats are liberal [liberal in the American meaning, not the correct meaning], the paper tested two main hypotheses which are based on key differences between conservative and liberal political philosophies. The first concerns egalitarianism and the second concerns the treatment of traditionally disadvantaged racial and ethnic minorities. We found that relative to their Democratic colleagues, Republican professors are associated with a less egalitarian distribution of grades and with lower grades awarded to Black students relative to Whites.

Professors control the allocation of grades which serve as the primary currency of academia. Our results suggest that the allocation of grades is associated with the worldview or ideology of professors. This finding may inform the public debate on potential reforms to university grading practices. To the extent that the application of objective standards is an important university goal, policy makers should consider limiting the discretion professors enjoy when it comes to grading and making it more difficult for them to use student characteristics as factors in the grading process.

Such results and conclusions will, no doubt, be controversial and we will see much heat, if little light, generated in the discussion that is sure to follow publication of the paper.