My analytical tools make various otherwise-elusive questions easy to answer, so while I'm playing with heavy-metal data, here's another thing I wondered about: which bands have the narrowest and widest ranges of ratings? To answer this meaningfully I counted only releases that have 4 or more reviews, and only bands that have 4 or more of these releases and at least 10 different reviewers. For these I then averaged the ratings for each such release, and ran standard deviations on the sets of averages. So a low standard deviation means there's some consensus that the quality of the band's output is consistent. High means consensus that the quality varies widely.  

Here are 25 most consistent. "Spread" is the standard deviation, "Average" is the average rating of the releases used in the calculation.  

#	Artist	Spread	Average
1	Coroner	0.908	88.21
2	Helstar	1.455	90.54
3	Moonsorrow	1.676	89.98
4	Dark Angel (US)	1.767	82.15
5	Candlemass	1.842	89.78
6	Lamb of God	1.845	68.5
7	Obituary	2.004	85.32
8	Type O Negative	2.035	89.16
9	Accept	2.193	88.06
10	Agent Steel	2.479	90.49
11	Fates Warning	2.531	93.36
12	Alice in Chains	2.538	88.83
13	Iron Savior	3.025	88.25
14	Falconer	3.083	84.42
15	Therion (Swe)	3.159	90.38
16	Sodom	3.294	83.4
17	Kamelot	3.463	90.52
18	Gorgoroth	3.496	84.71
19	Judas Iscariot	3.602	89.03
20	Bolt Thrower	3.652	88.31
21	Suffocation (US)	3.701	86.48
22	Angra	3.758	88.63
23	Enslaved (Nor)	3.926	88.85
24	Vader	4.162	85.78
25	Bal-Sagoth	4.249	89.9

 

I sense a hastily-assembled cash-in Coroner boxset in our future. I think this also means that Fates Warning is the most consistently great band in all of heavy metal. So now we know. And Lamb of God gets some sort of weird prize for being the most consistently mediocre.