Ivan Steiner

Who they are

The formula is a subtraction and it is pessimistic by construction. Whatever a group could in principle achieve, given the abilities of its members, the actual result is that minus whatever the process costs. Nothing in it allows for a group achieving more than the sum of what its members bring. Richard Hackman later added a gains term, which is why this site treats process losses and process gains as one topic rather than two.

The taxonomy is the half that goes missing. Steiner classified tasks by how individual contributions combine into a group product: additive, where contributions sum; disjunctive, where the group succeeds if any one member succeeds; conjunctive, where the group can only go as fast as its weakest member; and discretionary, where the group decides for itself how to combine what people bring. The classification is what tells you in advance which losses a given task will suffer and which it will not, and that is exactly the information the formula on its own does not carry.

He is the clearest case on this site of a researcher credited accurately and excerpted narrowly. The books that use the formula credit him properly and take nothing from the taxonomy. That is a gap in coverage rather than a crediting error, and it matters because a reader given the subtraction without the classification concludes that groups are a tax on individuals, which is a stronger conclusion than the work supports.

Key papers

His contribution here is a book rather than a paper, and this vault has not read it. Nothing is attributed to it beyond authorship and the standard account of its two contributions.

Steiner, I. D. (1972). Group Process and Productivity. Academic Press. The source of both the productivity formula and the four-way task taxonomy. External verification pass of 2026-09-23 confirmed the title, publisher and year. Not read here.

Key ideas

The productivity formula: actual productivity equals potential productivity minus losses due to faulty process. A subtraction, with no term for gain.

The task taxonomy: additive, disjunctive, conjunctive and discretionary tasks, classified by how individual contributions combine into a group product.

The taxonomy is the diagnostic and the formula is only the accounting. Which losses a group will suffer depends on which kind of task it is doing.

Hackman's later addition of a gains term is what makes the formula usable as a two-sided account rather than a verdict on groups.

Being credited correctly is not the same as being represented fully. This is the page that makes that distinction on this site.

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