Editing of prospects
Also known as: Editing phase, Coding of prospects
The pre-processing stage where a decision is simplified and framed before it is evaluated.
What it means
In prospect theory, choice proceeds in two phases: an editing (or coding) phase that organizes and simplifies the options, followed by an evaluation phase that applies the value and weighting functions. Editing operations include coding outcomes as gains or losses relative to a reference point, combining identical outcomes, segregating riskless components, canceling shared elements across prospects, and discarding extremely unlikely outcomes. Because editing happens first and depends on how the problem is presented, two logically identical choices can be edited differently and therefore evaluated differently — the formal root of framing effects and violations of invariance. The editing stage is also where many apparent inconsistencies originate, since the same person may edit the same problem differently on different occasions. It is the least formalized part of the theory but central to understanding why description matters.
Order decides the outcome
The operations are not a fixed pipeline. Kahneman and Tversky listed roughly six of them — the four usually quoted plus detection of transparent dominance and rounding of probabilities and outcomes — but gave no rule for the sequence in which they apply. Order matters because the edits interact: canceling a component shared by two prospects before, rather than after, segregating a riskless part can leave a different residual to evaluate. A pair of gambles can therefore look like a sure thing under one editing path and a genuine bet under another. Because a person reaches the same problem from different presentations, the same individual may edit it two ways on two occasions, which is exactly how the theory generates the framing effects and preference reversals a fully rational account forbids.
The theory's least formal joint
The editing stage is deliberately loose, and its authors said so. They described the operations qualitatively and admitted there was no formal account of when each applies or how conflicts between them resolve. That looseness is both an asset and a liability: it lets prospect theory absorb a wide range of framing anomalies, but at the cost of predictive discipline, since an unspecified edit can be invoked after the fact to fit almost any result. Critics have long noted that a theory whose first stage is a bag of heuristics can rationalize a violation of invariance without predicting which violations occur. The precise, testable commitments live in the evaluation phase — the value and weighting functions — while editing carries the descriptive weight but none of the mathematics.
What cumulative prospect theory kept
When Tversky and Kahneman rebuilt the theory in 1992, they moved much of editing's work into the formal machinery. The original version needed a detection-of-dominance edit because weighting individual probabilities could otherwise endorse a dominated option; the cumulative version transforms ranked cumulative probabilities instead, so it respects stochastic dominance automatically and no longer requires that repair. Coding relative to a reference point survived as the theory's core, but the looser simplifying edits — combination, cancellation, rounding — were left as informal preprocessing rather than defined steps. The upshot is that the editing phase, though still the standard story of why description matters, is largely absent from the equations most researchers now fit to data.
Where the evidence pushes back
The combination operation makes a sharp empirical claim: splitting one branch of a gamble into two branches with the same outcome should not change choices, because editing would merge them back before evaluation. Birnbaum's work on event-splitting finds the opposite. Presenting a prospect with its probability mass split across two identical-outcome branches reliably shifts preferences, a violation of the coalescing that editing assumes. These results, part of a set of new paradoxes, are awkward for both prospect theory and its cumulative successor and have driven configural-weight alternatives that abandon coalescing outright. The lesson is not that editing is imaginary but that its operations are not automatic. People do not always simplify in the tidy ways the phase posits, and when they fail to, choices move.
Examples
A purchase framed as a $5 surcharge for paying by card is edited as a loss, while the identical deal framed as a $5 cash discount is edited as a foregone gain.
Two mobile tariffs both include unlimited texts, so shoppers cancel that shared element and compare only the data allowances — the identical texts drop out of the decision entirely.
Skimming a travel policy, you discard the one-in-a-million catastrophe cover as effectively zero and never weigh it at all, comparing the plans on price and excess alone.
A job offer of a guaranteed $2,000 base plus a risky year-end bonus is edited into a sure $2,000, mentally set aside, and a separate gamble, so the certain part frames the whole deal.
Reviewing a retirement statement, an investor merges three funds that all rose into one 'up' quarter and codes it against last year's balance, so a mixed portfolio reads as a clean gain.
First described in Kahneman & Tversky (1979).
Key references
- Birnbaum, M. H. (2008). New paradoxes of risky decision making. Psychological Review, 115(2), 463-501. doi.org/10.1037/0033-295X.115.2.463
- Wu, G., Zhang, J., & Gonzalez, R. (2004). Decision under risk. In D. J. Koehler & N. Harvey (Eds.), Blackwell Handbook of Judgment and Decision Making (pp. 399-423). Blackwell. doi.org/10.1002/9780470752937.ch20
- Tversky, A., & Kahneman, D. (1992). Advances in prospect theory: Cumulative representation of uncertainty. Journal of Risk and Uncertainty, 5(4), 297-323. doi.org/10.1007/BF00122574
- Tversky, A., & Kahneman, D. (1981). The framing of decisions and the psychology of choice. Science, 211(4481), 453-458. doi.org/10.1126/science.7455683
- Kahneman, D., & Tversky, A. (1979). Prospect theory: An analysis of decision under risk. Econometrica, 47(2), 263-291. doi.org/10.2307/1914185