Bias and error are a few of the problems when doing scientific research, either quantitively or qualitatively. In quantitative research, random bias or error are those caused by unprecedented changes in the instrument or situation of research while systematic error has to do with the process and the design of the study.
Qualitative research, on the other hand, might have subjectivity bias where the authors point of view might be influenced by non-objective or biased personal perspective rather than seeing the situation with an objective eye.
