If she's constipated, I agree with the PP that it'll be almost impossible for her to know if she has to pee. There's too much pressure and discomfort already for her to be able to tell when she has to go.

How much water does she drink during a day and is she drinking anything else? I've never had to deal with constipated kids, so I'm not sure what to suggest. One of the kids wasn't generating enough urine to notice that he had to go, so we doubled his water intake for a few days (he wasn't drinking anything else, had been refusing milk for ~6 months at that point), and that worked to clue him in to how it felt. Other than that, keep working on MB to get a second opinion about constipation?

Yes I'm sorry to say both that I think constipation has been a factor (as mentioned in original post)and also that their pediatrician has been very unhelpful throughout this entire process (for those pps who suggested consulting the ped). MB has taken her daughter to the ped three times in the last year, first to just discuss beginning potty training (when the ped told her to use a timer but have it go off every 90-120 mins! That was right when she turned two and hadn't yet begun potty training so that set off a red flag for me because that time frame was too long). Then a second time when after six months potty training wasn't making progress (ped said she's fine physically and just to keep trying). Then the third time was about four months ago, when I discussed with MB that DD was exhibiting classic constipation symptoms and had been for months (having frequent tiny poops and then one large painful poop once every 7-10 days, etc). Others I spoke to said the doc should consider a laxative, or at least an x Ray to figure out if she was impacted etc, since we had already been giving her prunes and ground flax seeds daily and she had been eating lots of whole grains and fruits also to no avail. But the ped just said laxatives and xrays weren't necessary and she was fine :/ I told MB I'd consider getting a second opinion but MB said this ped came highly recommended from friends with older kids and she trusted her.

11:56 I really like the watch and blue water suggestion, thank you for that. I'll bring up those ideas to MB.

Perhaps instead of a timer, get her a "potty watch" (which is the same as a timer but may be different/cool enough to work), because she is a big girl. When the potty watch goes off, it is time to go potty. Also, try not to talk about whether she "needs" to go potty, but rather whether she "can" go potty. So perhaps she doesn't think she needs to go, but she could go.

Another thing my kids love is the blue colored toilet water -- they like to be able to turn the blue water to green.

Finally, if she is constipated, which can happen during potty training, she may not be able to feel that she has to pee. So I would make sure that is not a problem first.