Its not a massive sample, is it?
When I was in teacherās college, most of the research papers involving studies of students were written by one or two teachers trying out things in their own classrooms.
You want a larger study involving many different schools over a long period of time? For the science of it, it should be done, but because itās education, even college-level education, the bureaucracy and ethics debates make it difficult very, very quickly. More feasible is to do a series of small studies like this and then have the researchers compare notes with each other. Fingers crossed that now that this paper had been published, more schools will replicate the experiment and compare results.
No, but it provides evidence that a larger study (possibly over several different course topics) is worth while.
I knew that was coming in the comments here, but didnāt quite expect it to be the FIRST comment. Sigh.
Ask women who teach; this study merely confirms common knowledge among them.
Like other professionals who recognizably exist in other subjugated groups, most wome who teach know that generally, they arenāt automatically granted the same levels of authority and respect that men are. Getting that kind of respect (and thus, for one thing, higher teaching evaluations) means dressing more professionally, acting more strict and āin control,ā constantly performing a balancing act between āfriendlyā and ābitchy,ā and yes, as the studyās results exemplify, having grades challenged more often.
I was going to comment that I thought it odd that people would rate people on their interpersonal skills when they hadnāt seen or heard them, then I realised I do that here 
Maybe someone should set up a poll to do this for regular users here? (No. No they shouldnāt).
Maybe people expect more from a female teacher.
Thereās plenty of studies already that show that women, people of color, and queer people get lower ratings when they teach in-person classes. This just adds the online dimension and thus the opportunity for a study that separates out gender prejudice from any actual differences in teaching style.
And yet, all of us who are faculty still have our retention and advancement tied to these evals. Itās hateful.
Welcome to sexism!
Er, yeah, thatās pretty much the pointā¦and the problem.
Are you saying they SHOULD expect more from a female teacher?
I think itās a fair observation, though. It almost certainly matches reality, but itās just an observation that itās not really a proper study.
Heck, Iāve noticed that when I use the handle I usually use on websites, one that ends in āaā, people, especially those who speak Romance languages, behave badly toward me until they figure out Iām a dude.
That implies something more is at work than just higher expectations for female teachers. I canāt say Iāve ever heard someone say that queer folk are always better teachers (although I have frequently heard that stereotype applied to women). Better interior decorators and hair stylists, yes, all the time, but never better teachers.
Cloud research 
I think what it comes down to is that people have prejudices and think worse of certain groups and then apply a rationale to that after the fact. Give a female teacher a worse rating, get confronted, and think to yourself, 'It must be because Iāve had such good experiences with female teachers that I expected more of them."
The reasoning comes after, so basically itās hogwash.
Itās not that itās impossible to have a good reason to think one thing over another, itās just that an awful lot of the time we should of peopleās reasoning about why they feel certain ways (including our own). First we feel things, then we go to work trying to make sure we arenāt called stupid for feeling them.
A future version of this test might include making it double blind, so that the teachers donāt know if they are being presented as male or female to remove any unconscious bias on the their part.
The explanations are multiple:
Students seem to expect female professors to be more ācaringā and ānurturing,ā so women get dinged harder than men for not giving extensions on assignments, assigning lots of reading, not giving in to studentsā sob stories about why they should get harder grades, etc. Female professors also get criticized about their appearance a lot - too frumpy, too sexy, too young, too old, too much makeup, not enough makeup, etc.
Queer people and people of color (and women who identify as feminists) get slammed for being ābiasedā in their teaching, for having an āagenda,ā for disliking [insert whatever majority group here], for being āangry,ā and also for having high standards (being āmeanā or āuncaringā). (They also get assigned to teach general courses on multiculturalism more often, and those courses always get lower ratings even when taught by white men, so minorities are more likely to get double dinged - for being who they are, and for the class content.)
People of color get rated as less professional, less competent, less experienced, etc. no matter what their actual objective years in the field are. They also get labeled angry, abrasive, loud, etc.
So there you go.
My weasel word detector is off the scale.
What part of the study is flawed?
I ālikedā your post because you gave us all (and particularly me) some insight, but if there was a āhateā button Iād use that for the situation you describe. 
Yep. You really do have to work harder to gain your students respect at the beginning of the semester (the male grad students just tend to get it right off), and they really are harder on you in the evaluations. On top of that, there is almost always that one guy - itās nearly always a guy too - who just will never give you the respect for getting to the point of working a PhD in your field. Iād guess itās even tougher in STEM fields, too.
What more should we do than our male colleagues? I donāt understand why I should be held to a different standard in my work and my teaching than my male colleagues? Why should I have to put up with that?
