Okay, as I quite like
@Denkt testing posts, and realize hard data is often more reliable than my own gut instinct I decided to shut my flapping little mouth, stop filling the forums with ill considered garbage for a couple of hours and do some actual testing.
I'll try to turn it into a spreadsheet a little later, if anybody really wants the data.
To test the impact of variant production to my own satisfaction I did the following:
- I ran two games as the UK, both starting in 1936, with the AI turned off.
- I increased the number of MILs to 20 and used all on one production line.
- I cleared all production lines, and on the 1st of each year Where a new Industrial tech was available, I implemented it.
- I chose light tanks to be my testbed piece of equipment
- Every 6* months I either swapped production if a new light tank was available that year, or I created a variant and switched to it **
- I made no changes to the starting economic laws and made no different choices in the few popups that appeared
- For 5* months I produced Vickers 2, then swapped to Matilda, and then swapped production every January 1st or June 1st* I did not use PP to increase output at any time
- Where a new industrial tech was researched I waited a day for it to take effect before switching production so that it's bonuses would apply.
- I intend to, but have not yet, run a control producing only new models and not any variants.
On 1st Jan '38 production looked like:
- CI - 10.7 units per day @ 66.24% eff, total light tanks: 4654
- DI - 10.31 units per day @ 68.02% eff, total light tanks: 4633
On 1st Jan '39
- CI - 11.33 units per day @70.08% efficiency, total light tanks: 8620
- DI - 10.63 units per day @70.08% efficiency, total light tanks: 8422
On 1st Jan '41, the last day of production for Matilda variants before switching to Valentine
- CI - 13.75 units per day @ 80.08% eff, total light tanks: 18396
- DI - 12.55 units per day @ 80.08% eff, total light tanks: 17535
Switching to Valentine of crashed the CI line to 24.02% starting efficiency, the DI line started back up with 46.50% efficiency
On 1st Jan '42
- CI - 12.93 units per day @ 77.05% eff, total light tanks: 21755
- DI - 13.02 units per day @ 86.83% eff, total light tanks: 21279
On 1st Jan '43
- CI - 15.13 units per day @ 90.09% eff, total light tanks: 26806
- DI - 13.51 units per day @ 90.09% eff, total light tanks: 26131
First thing that stands out is that until 1939 tech arrives the difference is minimal but noticeable if you have large amounts of MIL on one thing, beyond that even at the same efficiency level Concentrated just produces more units per day. That's not entirely unexpected.
Beyond '39 I would have expected the lower amount of efficiency lost by DI to have a greater impact, and it does but only in the short term, as the efficiency of the Concentrated line rebounds faster than that of the dispersed line because of diminishing returns as they both get closer to their cap combined with the higher overall production of CI. The CI production line in 41 took a big blow when switching to Valentine, and despite new variants every 5th and 7th month, it had mostly caught up within one year.
The end results confirm and deny my original thinking in interesting ways.
They say Valisk you are wrong about variants, the CI line can handle them as long as you are not a crazy monkey spamming variants every time you get 25xp spare, and will probably out perform DI if you batch the variants every 6+ months, and more to the point I think it looks very reasonable and balanced to do that.
They also say Valisk you are right about the heavy crashes in CI efficiency after switching pinching production, don't be a simpleton and switch to that new rifle/tank/plane if you are in the middle of a severe crisis with your equipment as you did with the USSR thinking the extra stats would be very helpful, that is dangerously stupid.
And they also validated my not entirely unobvious instinct as the USSR to build my CI factories way up North, far out of the range of bombers.
I've not controlled in any way for bombing damage, which is obviously a consideration, but in the immediate aftermath of proudly producing 52,000 tanks in my factories I can say that my first thoughts are (and I appreciate that this may already be obvious to most of you) that any one planning to play as an Arsenal of Democracy(tm) in MP should probably divvy up the production responsibilities so that they are hammering out items with no variants and for those with long runs but potential variants then make minimal changes as infrequently as possible, and either skip every other model (medium tanks looking at you) or have the countries with DI systems produce those particular types of equipment.
* I decided to split the 12 months into a 5 month and 7 month period to see if Dispersed would catch up production in the short term, and lose it vs a longer run for Concentrated in the long term, I did not at all make a mistake during the 1st year and decide to just double down on it because I thought about it for a moment when about to restart the experiment and discovered it might be useful, no sireee not me!
** I did test if adding 1 or 5 points to the variant increased the drop in production efficiency and it doesn't which is also useful information.