charles1dad
There are limits to expectation bias, however, so it shouldn't be cited as the cause for every result. For example, I have sometimes made a system change that I was sure would make no audible difference, only to be surprised that it did result in a difference. The opposite has also happened to me. So it is a rather unpredictable form of bias.
... I’m sure most reasonable people will acknowledge that "expectation bias " is applicable to both positive and "negative " positions. . You can certainly be convinced that something is not possible and this adamant mindset potentially inhibits the possibility of fair and open minded assessment ... to accuse those who do hear improvement as simply suffering from expectation bias (which is possible in some cases) the converse is just as valid for the deny campers as well.This is absolutely true, and often overlooked. Oddly, those who consider themselves objectivists often dismiss their vulnerability to expectation bias.
There are limits to expectation bias, however, so it shouldn't be cited as the cause for every result. For example, I have sometimes made a system change that I was sure would make no audible difference, only to be surprised that it did result in a difference. The opposite has also happened to me. So it is a rather unpredictable form of bias.