The +300% productivity cap should be documented in-game or removed

[xylo]

TL;DR

The +300% cap on the productivity bonus is not documented anywhere in-game; it should either be mentioned in the Factoriopedia or (preferably) removed entirely.

What?

Factorio has many gameplay restrictions currently undocumented in-game. Such restrictions should be either documented or removed. The worst offender IMO is the hidden productivity bonus cap at +300%. It is especially bad since the game strongly hints that no such cap exists, and since the player needs to spend at least 580k automation, logistic, chemical, production and electromagnetic science packs to reach "processing unit productivity 13" and possibly hit the cap. That's a lot of resources to spend before realizing that the recycler loop the player was likely planning to use is not actually allowed by the game.

The reasons a reasonable player could think there is no productivity bonus cap are:

1. The efficiency module description mentions the efficiency cap. The productivity module description doesn't mention the productivity cap. A player will expect consistency, and deduce that any description not explicitly mentioning a cap means that the corresponding bonus is uncapped.
2. The productivity technologies are all infinitely repeatable. If the productivity bonus was capped at +300%, surely the repeatability range would have been 1 — 30 instead of 1 — ∞, right?
3. The large amount of science required, the fact that the there would be no way to "dupe" any item whose raw materials include stones, uranium, or any planet specific resources or items, and the fact that processing units have a liquid ingredient all suggest that the game was actually balanced with recycler loops in mind for the late game.

BTW, the other undocumented restrictions in 2.0.15 I can think of are:

• The construction surface conditions of the cargo landing pad don't mention the 1 per surface limit
• Module descriptions don't mention which modules cannot be used in beacons
• The productivity module description incorrectly implies that they can be used for all intermediate products
• The productivity module description misleadingly suggests that they are allowed on a product basis, while they are allowed on a recipe basis (for example, they are allowed for producing nutrients from everything but fish)
• The concept of catalysts is not explained anywhere in the game, as far as I can tell

Ideally, all those restrictions should be either documented or removed. In the case of the productivity cap, I think a removal is the best solution.

Why?

Factorio requires planning, and it requires that the player knows the rules. If a player encounters an undocumented gameplay limitation only after having invested time and resources trying to do something the game does not allow, it hinders planning and feels frustrating, especially when the amount of resources wasted is big. It also breaks the principle of least astonishment.

Generally speaking, a good rule set has as few exceptions as possible, so the best way to solve undocumented restrictions is to lift them, or to rework them so that they are no longer necessary (for instance, why not simply put the recipes that don't work with productivity modules in another category than "intermediate products"?). Of course, documenting said restrictions does the job too, but it feels like a less satisfying resolution. In any case, it is not a good idea to leave important gameplay restrictions undocumented in-game.

Notes

There are already mods allowing to remove the productivity cap. I thought I'd share my reasoning anyway.

[Dixi]

I have a feeling, that author of this post is a lawyer
A lot of games are about exploration, and unpredictable results one can meet on a way or in the end.
Factorio actually has much more information displayed and documented, compared to many other games.

Okay, xylo, you planned to make endless resource production recycle factory but fails due to unannounced game limitation. I think you still had fun on a way, and this shows only that you plan was predicted and limited by Wube. For some reason they decide that endless resources from recycle is not a right thing. Since Space Age already has many endless things, like lava, asteroids, plants, I see no problem at all in this part of game design.

[CyberCider]

I mean, the cap has to exist. It exists to prevent infinite item duplication using recyclers. That has no place in vanilla. And as you said, if a mod wants to make it possible, it can.

[BlueTemplar]

The realistic way to do this (which would also make this cap obvious) would be, for instance, to scale it all down by 4, so default recipes are considered to be wasting something like 75% of their ingredients, and productivity can raise that somewhat (and probably with diminishing returns, so you never actually hit 100% ingredient efficiency, but approach it asymptotically).

But I guess this would make the early game more complicated to figure out
(maybe not the very early game — only when starting to use productivity, since before it wouldn't change anything ?),
which is why Wube didn't go with it
(and also why they removed fuel to power (in)efficiency on vanilla boilers and/or steam engines).