Construct alternatives from the contribution that is at risk

Recover the required meaning and the observation before diagnosing the participant. Ask which difference in their interpretation, available information or planned action could produce that observation and make the receiving contribution fail. For each plausible account, say what you would explain, request or do differently if it held. Keep accounts together when their distinction changes no available action. These hypotheses concern the present continuation. A.3.3.PI explains how to recover a consequential distinction hidden by an otherwise identical description, retain alternatives and update them from an observation.

Consider this constructed engineering case. Two participants receive the same brief, source tables and rule: compare variants A and B using the limiting fractional margin m = capacity / demand - 1; a case passes this supplied numerical rule only when m >= 0. Preserve the source of the values and check the decisive inputs directly against that source, independently of the integrator’s copied calculation. They may prepare the comparison; they have no permission to change the design. Case 17 has capacity 80 and demand 100 in the same units. Its ratio is 0.8 and its margin is -0.2, so it fails the rule.

The collaborator writes: “Case 17: reserve 0.8; I can continue checking.” One failed continuation is to assume both correct understanding and the intended source check. The later return treats 0.8 as positive reserve and repeats arithmetic from the integrator’s copied values. The comparison then has a wrong interpretation and lacks the required source check. Resending the identical brief does not establish which assumption needs repair.

Return to the initial message with that common input unchanged. The expression “reserve 0.8” is consistent with confusing a capacity/demand ratio with surplus, but it could also be an imprecise label from someone who understands the margin. The planned “check” could revisit the original source or merely recalculate the copied table. The first uncertainty changes the explanation; the second changes the division of work.