"In general, portfolios aren’t required for UX research roles today."
So concludes this article that I had a feeling I would have opinions about when I clicked on it.
Is this true? The short answer is...

Now that we have that out of the way, here's what I know
In my 10+ years as a UX researcher, I can tell you that this is simply not true for most people and most job search situations. Speaking for myself, I can't remember a time when I wasn't asked to present examples of my work, including for entry to senior level roles I applied to, and for client pitches when I was a consultant. When I began my career, I realized that a portfolio (both online and a presentation version) would be crucial for standing out from other candidates.
How did I figure this out? I was literally asked to share my work in the interview process. I talked to enough people to know that it's a common expectation in the design world, where a big part of our job is to communicate with others verbally, visually, and in written form. And I put pedal to the metal for self-learning about UX as a field and practice, and how to get a job doing it. This was the standard advice all the way back then, when there was 1/100th of the amount of information on UX that's available today.
Since then, every hiring panel I have ever been on for researchers (and designers, naturally) required candidates to do the same. Additionally, I can't think of a single client of mine in the past year and a half who didn't need to present at least one UXR case study while interviewing for entry to senior level roles at a range of companies, from places like Google and Facebook, to startups of all sizes, and even academic institutions. In addition to presenting case studies, most of them had their work available on their personal website.
As usual, it depends
This is not to say that getting by without a portfolio has never happened before. I have no doubt this happens, but not to the extent the author states. There are several factors that may come into play (hypotheses that could be tested). If you are highly experienced, have a good reputation, and get a referral, you may be able to land a job or project without having to show your work. You definitely need a website with some semblance of who you are and what you've done, but you don't need to post detailed case studies.
Your experience may also differ based on whether pitching for a consulting project versus applying at a company. There's also cronyism and gender (and other) biases in the hiring process. Or, perhaps you are moving into UXR from a research-adjacent role, like research operations or project management. Perhaps you don't have research case studies, but you do need to be able to talk about (and likely showcase) your relevant work experience, and ideally in case study format.
We need to consider the sample size and origin.
This person's sample is a decently sized convenience/snowball sample, meaning he reached out to people he knows and they connected him with people they know. I don't know who these people are, so I'm not sure about their backgrounds, experience level, where they work, where they were recruited, their gender, industry, etc.
The same can be said about my own sample (which includes myself, people I have worked with, being on hiring panels, and my clients). This gap in knowledge makes it difficult to understand why we both came to such different conclusions. That said, I feel pretty confident in my conclusion because of how long I've been in the field and my sample size accumulating over 10 years (I don't know the exact number from over the course of 10 years).
I'm still very curious because I want to make sure I have the most accurate understanding of this topic when working with clients. And I am always open to new information and interpretations. Clearly someone needs to do a qual/quant study to better understand what's going on here! Or maybe I should talk with this guy and see what we come up with.
One more thing--we need to define what we mean by "portfolio". I've noticed that this word can imply different things: a website with work examples, a PDF file that you send as part of your application, or case studies you present during an interview.
Actually one more thing. We also need to talk more about how to effectively interview UXR candidates, and the purpose that a portfolio can serve in addition to other methods like project hypotheticals, behavioral questions, being interviewed by people outside of the research team, etc.
What others think
Naturally I decided to post about this on LinkedIn to get other people's thoughts (which makes my sample better, too!). As you will see, most people concur with the need for a UXR portfolio.