The way that I came up with the name, was that someone was suggesting that my taking metrics might create a placebo effect, where people would believe that they were doing better than they actually were.

So, my response to this was that I was not trying to create a placebo effect, but rather, to avoid a placebo effect in the opposite direction.

So while I agree with you that this effect is not an opposite (why I referred to it as related instead of reverse), I do think that it is the opposite of what a lot of people fear - that they are experiencing a placebo effect.

In short, people being afraid of having a placebo effect is often how this effect comes to be - they don't want to create false hope and then have it dissipate, so instead they refuse to believe or acknowledge real positive results when they see them.

So, I would say that the title is reasonable regarding people's expectations, but not in the precise using of the term placebo sense. Personally, I think that expectations are more important for titling. Fewer people will pay attention to a precisely named definition that they know nothing about, whereas calling it the anti-placebo effect grabs attention - specifically the attention of people who have this bias.