Averages: (see central tendency measures of)
Bias: Dictionary definitions of 'bias' vary but generally centre on the notion of distortion of judgement, prejudiced outlook, unfair influence. They sound reasonable enough but there can be problems over interpretation because one person's 'fair and unbiased point of view' may well be judged to be 'prejudice' by another. In Part 4 of the book, we asked whether there were any signs of bias in Jan's review of the literature. Had she selected only those items which supported her point of view? Had she used any inappropriate language which might have indicated strength of feeling in one direction? She recalls that it was her constant questioning of practice and her critical attitude towards the interpretation of data which helped her to recognize signs of bias. She was personally involved in her selected area of research and knew she had to consider the extent to which her value judgements might influence the way she interpreted research findings and her own data.
In Part 5, you will recall that Tim was concerned about the lack of an agreed definition of 'bias' in the literature. He found that writers rarely declared their assumptions and though many research reports claimed steps had been taken to eliminate bias, there appeared to be no agreement about what it actually was. One definition was that 'it is a circumstance that unduly influences teachers' ratings'. Sounds reasonable, but he found that was difficult to test. Another was that 'student ratings are biased to the extent that they are influenced by