research bias is of 7 types:
design bias, selection bias, measurement bias, interviewer bias,response bias and reporting bias, procedural bias.
now why these biases happen at all?
my hypothesis is:
1] researcher is under pressure to generate desired result by financier.
2] researcher has little knowledge about subject
3] researcher has limited knowledge about design, procedure, sampling, measurement etc.
4] fear of the world and peer pressure [ new theory/finding are not welcome always]
which one or two or three will be the answer?
if there are other causes, please mention.