What reason has been given for the "standard array" being lower than the expected average from the rolled method?

Question

When one levels up and gets an increase in maximum hit points, one can either roll or take the average roll rounded up. Statistically, you're better off with the non-random method.

For ability scores, the standard array is 15, 14, 13, 12, 10, 8. Using the point-buy system yields scores in this same basic range. But, according to AnyDice, the average rolls for 4d6-drop-one are 16, 14, 13, 12, 10, 9 — slightly better and, crucially, providing the likely possibility of an 18 to start (with a racial bonus of +2) and a 40% chance of starting with at least one ability score at 19 or 20.

It seems odd to me that the designers didn't go the same route as with hit points: make the predictable choice be rounded up from the average. This answer delves into the math and makes the same basic point — and ends up wishing that the designers had picked a slightly higher standard array.

We can all speculate on the pros and cons of this; I'm curious instead about designer intent and official references and commentary.

I'm voting to close this question as off-topic because Designer Reasons — David Coffron, Jun 21 '18 at 17:55
For reference: Designer intent questions are considered off-topic on RPG.SE. — V2Blast, Jun 21 '18 at 18:25
Eh. This question was asked and answered with an actual designer reference before that policy existed. And from the most-upvoted answer to that meta question, Refrain from any campaign to root out and close old questions. — mattdm, Jun 22 '18 at 00:43
@mattdm Refraining from a campaign to root out and close old questions is true, but doesn’t amount to a blanket grandfathering order. When someone stumbles across one in the normal course of using the site it’s fair game to close. (I’ve historical-locked this since it is currently off topic and reopening off-topic questions isn’t useful.) — SevenSidedDie, Aug 02 '18 at 21:18

score 16 · Accepted Answer · edited Aug 02 '18 at 19:35

16

Mike Mearls tweeted the following on 13 Jul 2014:

IIRC, point buy models the most common outcomes of 4d6, drop lowest.

(Emphasis mine. IIRC stands for "If I remember correctly". I didn't know that myself. :))

His tweet seems to imply

That they relied on some other probability calculation tool instead of AnyDice
The designer intent was, indeed, to use the most common outcomes of 4d6, drop lowest.

(The short thread Mearls' answer appears in discusses ways and whys of adding / not having a 16 in the standard array.)

edited Aug 02 '18 at 19:35

KorvinStarmast

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answered Dec 19 '17 at 18:03

OpaCitiZen

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Hooray! A non-speculation answer for this! Thank you, and great find. :) – doppelgreener Dec 19 '17 at 18:12

What reason has been given for the "standard array" being lower than the expected average from the rolled method?

1 Answers1