It depends on the question!

AskHistorians requires that answers be in-depth, comprehensive, and supported by current scholarship. So let's look at some of the ways that the scholarship itself relates to questions asked on AH.

Sometimes, questions here directly reflect the questions asked and answered in scholarly research, and there is consensus on the question. For example, people have asked before "Did medieval parents love their children." This is obviously not a straightforward "X happened and Y happened and Z said this" question. There were several major earlier studies that studied various evidence and argued no (Lawrence Stone and Philippe Ariès in particular). However, today, there has been enough reseaerch that modern scholars agree the answer is yes.

In this case, to reflect current scholarship, an AH answer would necessarily have to be "yes." Of course, it's up to the answerer to decide what evidence is required to make their answer "in-depth and comprehensive." But in the sense of new ideas--nope.

But the AH community often asks questions that differ from the way that scholars ask questions, or from scholarly questions entirely. For example, you're not going to find a university press publishing books on the history of drunk snacking. In that case, I had to make my own choices on: how to approach the question (I chose "the relationship between drinking alcohol and eating"), a scope for the question that I thought suited 'in-depth and comprehensive' (briefly medieval/early modern Europe; mainly US white/mainstream culture), and so forth.

Other times, users ask questions where scholarship disagrees on a topic--for example, why there are so many funky-looking snails in late medieval art. In these, you can either say there's a debate and give multiple sides without coming to a conclusion. Or it might be a topic where the answerer, as a historian, has a very definitive opinion. I will die on the hill that the Middle Ages ended in the 1520s, for example. (That's not my most eloquent post here, but you get the idea.)

In all seriousness, the different relationships between the questions asked by scholarship and the questions on AH are a lot of what makes it so fun to participate here. Since modern western scholarship approaches history from a very tight, restricted angle, AH offers a chance to think much more creatively about the past.

And, y'know, to talk about the history of drunk snacking in America.

I find it is always wise to bow in the direction of the Sun, so nothing need be added after /u/sunagainstgold has weighed in.

That said ... I am always most comfortable answering questions on topics I have previously researched and where I have related publications. That doesn't always happen, however. In addition and as Sun indicates, questions often take a direction or approach the subject with an angle that may not have been tackled by scholarship. Yesterday there was a question about variations in ancient epics. In the past months, I have been discussing this with a Polish expert on Homer who is asking much the same, but I found it useful to bring observations from one of my recent publications to address this with a different angle, inspired by the way the question was asked. The answer includes personal conclusions, especially with the final three points.

The point here is that /r/AskHistorian questions are frequently inspiring - they make all of us think about the past in different ways. Frequently, this requires "personal observations/conclusions on the subject."

Even more in my case, for the last nine years (almost!) I am studying the discourse on this subreddit to develop an understanding of modern folk assumptions and perspectives. Many questions dealing with folklore begin with something along the line of "We all know that there is an element of truth behind every legend, so could the legends about [fill in the blank] have been inspired by [fill in the blank]." The persistence of those questions made me realize that we do not "all know that there is an element of truth behind every legend," but rather that this is a modern folk belief. It is part of our folklore. This has helped me frame answers on this sub, but it is a personal conclusion based on my observations of the subreddit, where it in turn becomes part of the answers. This subreddit consequently adds to my ability to answer questions.

It depends? Given I often answer questions about where the ding-dong sound in doorbells comes from and Shrek, sometimes I do, indeed, need to do original work, just because they're topics not well-covered in scholarly literature. You can consider the final part of those answers to be "personal conclusions"; they're still supported by primary sources, just not secondary ones because they don't exist! (Even the one scholarly animation history work that went up past 2001 I used didn't discuss Shrek specifically.) My heaviest primary/secondary source ratio has to be my answer on Dungeons and Dragons behind the Iron Curtain, which had to rely almost entirely on primary sources, and the only reason I felt comfortable doing so is that it closely aligns with my Research research, and I had some part of the answer lying around already. (Which is on, for the curious, interactive fiction, adventure games, and gamebooks.)

Even when I'm drawing everything from other sources, it doesn't mean anyone has done a synthesis in a particular way yet; my answer about reactions to The Exorcist has every part of the conclusion drawn from scholarly work, but no source I'm aware of lists every one of those reasons, just one or two each.

I think the clearest post I've ever had related to this is my recent one on Egyptian mummies with detected cocaine. Part 1 was mostly describing the argument of my main source, with some secondary parts for clarity; Part 2 referred to a scholarly source, but was entirely about critiquing a piece of data in a way that was original.

Incidentally, "quoted from" isn't quite people are doing -- the art of selection and removal is itself a sort of history-making. Even in my more authoritative sources I've found some arguments to be weaker (or even contradicted by later references!) so a fair amount of decision making is still required.