When interviewing people, I don't need to see previous work product. I need them to talk about what they've built, why it was satisfying and what was hard about it. I've found that in less than 10 minutes I can establish whether someone worked deeply on something and understands what they've done. After 30, I can tell whether they're exceptionally proficient and if we'd enjoy collaborating.
As to coding chops, I think that has to be solved via asking them to code a solution to something on the spot (or perhaps in advance). That's far from perfect, but I don't think you need a portfolio, per se.
Although, if you have lots of stuff that's publicly available, that's clearly a bonus. But that's not an option for many people.
Maybe I'm an outlier, but I cannot talk proficiently about a project I haven't worked on in months. When it's in my brain, I am living and breathing it, but afterwards if I'm asked to talk about it, it stumbles out as I try to recall the pieces. I can rehearse beforehand, but it becomes clear as soon as the interviewer does any digging, that I don't remember the details.
Ask me to code something beforehand and I'll excel at it, but ask me "what's going through your mind" as I'm coding it and I'll sound like a scatterbrain. I need time, low pressure, and privacy to code well.
>I need time, low pressure, and privacy to code well.
Me too. I've had jobs where I had to work in areas with high foot traffic, lots of distractions, I could never get in "the zone" and never got any real work done. Well, looking back, I did get some work done, but I always felt like I was too distracted to focus, and it definitely took me a lot longer than it would have otherwise.
As to coding chops, I think that has to be solved via asking them to code a solution to something on the spot (or perhaps in advance). That's far from perfect, but I don't think you need a portfolio, per se.
Although, if you have lots of stuff that's publicly available, that's clearly a bonus. But that's not an option for many people.