Amazon.com reviewer rank

Factual Questions
1

As an avid reader, I make at least a daily pilgrimage to amazon.com and various other online booksellers. I particularly appreciate amazon because of its reader reviews, which often factor into my buying choices, and I sometimes review books myself. After I began reviewing books, I began noticing that amazon ranks its Top Reviewers (so far I have reached 2793rd), but I can’t figure out its system–the rankings usually seem arbitrary, and sometimes even counterintuitive. For example, here are the Top Reviewers ranked 35th (the first tied ranking shared by at least two reviewers) through 54th:

Rank----Reviews Written----Helpful Votes----Votes per Review
35----4075----6679----01.64
35----1372----4309----03.14
37----0377----5045----13.38
38----0861----3951----04.59
38----0326----4591----14.08
40----0629----2527----04.02
40----0452----3293----07.29
42----0323----3622----11.21
42----0380----5677----14.94
44----0259----4329----16.71
44----0845----3068----03.63
46----0298----6229----20.90
47----0438----3371----07.70
47----0799----5016----06.28
49----0276----3082----11.17
50----0501----2415----04.82
51----0545----3261----05.98
51----0433----2486----05.74
53----0871----2643----03.03
54----0829----2256----02.72

Presumably writing more reviews is better than having written fewer reviews, earning more helpful votes is better than fewer helpful votes, and earning more helpful votes per review is better than fewer votes per review. But of the reviewers tied at 51st, one has written more reviews, gotten more helpful votes, and gotten more helpful votes per review than the other, yet they are tied. Top Reviewer 46 has written more reviews, gotten more helpful votes, and gotten more helpful votes per review than a reviewer tied for 44th, yet comes in behind. How is amazon calculating these ranks?

I suppose that votes that a review is unhelpful may be factoring in somehow, although gathering that information would take more effort than my curiosity warrants. But does anyone know how amazon calculates its reviewers’ rank? or see a pattern in these numbers that suggests any predictability?

2

Did you see the Reviewers FAQ page?

At one point it mentions:

So it seems your theory that negative votes affect the calculation is correct.

3

Thanks, milquetoast, I had missed that point (since it appears in a question headed “I’ve noticed badges next to reviewers’ names. What do they represent?”).

Again, I haven’t run the calculation, but it seems unlikely that the “unhelpful” votes can entirely account for the discrepancies.