EAM.10:4 - Solution
Define complete choices and different kinds of coupling
State the portfolio scope, requested result and horizon. Recover the alternatives and their eligibility from EAM.7–EAM.9. Identify which choices are mutually exclusive, mandatory, optional or dependent, and why. Include continued use or no new work when it is a qualified alternative. An omitted asset can still matter through a shared service or resource.
Distinguish three questions about a proposed combination. A prerequisite or exclusion determines which selections can coexist: a new unit may need an enabling connection, while two replacements for the same role may be mutually exclusive. A shared resource limit constrains the work or use at a particular time: two eligible jobs may need the same crew or exceed an outage allowance. A joint consequence changes what happens when the choices are taken together: common mobilization may reduce cost, while simultaneous demand can require additional provision. One arrangement can create all three, but each needs its own evidence.
For each material relation, identify the affected alternatives, its operating or engineering cause, the time and conditions under which it holds, and the resulting constraint or consequence. EAM.6 supplies service and dependency conditions. A promised saving cannot make a combination technically eligible.
Construct the whole consequence account
Start from compatible policies on the same service boundary, perspective and horizon. If a policy omits later support or its ending, return to EAM.8. Then describe what work and service the combination actually entails. Identify shared preparation, enabling work, recurring operation, temporary service and ending consequences. Obtain amounts and dates for those actual operations.
Reconcile this whole account with the separate accounts. For costs on the same basis, joint adjustment = whole-combination cost − sum of standalone costs. A negative amount is a saving; a positive amount is an additional cost. Explain what causes it and when it occurs. Where effects differ by date, construct the dated differences first and obtain their financial value through FIN.9 on the applicable basis. FIN.9 develops this interaction comparison and dated funding constraints; its return must identify the combination, common baseline, perspective, amounts, dates and significant assumptions.
Count each shared consequence once. If two estimates each contain the same mobilization, the combination that uses one mobilization retains one payment. If three jobs share it, reconstruct their common account; summing all three pairwise discounts could remove more mobilizations than were included. If sharing requires extra supervision or temporary service, include that cost too. An allocation of common cost among departments does not by itself create a saving in the whole payment.
Keep unpriced consequences visible. Shared disruption can change a service or environmental result even when the expenditure sum is unchanged. Use EAM.9’s actual criteria to compare those consequences; a cash adjustment cannot silently settle them. When the combination changes a demand or recovery premise, return that premise to EAM.4 or EAM.6 before relying on its qualification.
Test constraints and compare the feasible combinations
Write the constraints at the whole-combination scope. Separate initial capital, initial operating expenditure and recurring operating envelopes where they are different decisions. Include later commitments when they bind: the year-three overhaul in an EAM.8 policy needs its funding, crew and service window at that time. A low initial outlay does not establish that later provision. Do not count a resource twice or assume unused funding must be spent.
Enumerate a small finite set of indivisible choices. For the CityWater shortlist, choose exactly one of two options for each of four stations and compare all sixteen. For a different question, the feasible no-work, single and combined choices depend on what service is mandatory. Remove combinations excluded by a supported prerequisite, technical condition or resource limit, retaining the reason. Obtain a feasible service-preserving calendar through EAM.11 where timing can defeat an otherwise eligible selection.
For a larger problem, select an optimization or scenario method whose objective, choices, constraints and interactions represent the actual question. Specify what is selectable, which selections imply or exclude others, dated resource use and the joint effects. Model contingent actions with the information available when each action is chosen; the combination cannot assume different early choices for future outcomes that are not yet known. A mathematical optimum applies to the represented set and basis.
Compare eligible combinations using the actual value criteria. When required service and other material consequences are equal, minimize total present cost. Otherwise preserve justified trade-offs or a non-dominated set. A cheaper programme that requires more scarce resources does not automatically dominate a dearer one.
Explain the choice and the condition that could change it
Show the preferred combination and the consequential alternatives it displaces. Test a changed funding limit, engineering qualification, demand driver, shared-work condition or resource date when it could alter the answer. Use coherent conditions across the combination; a common disruption cannot be favorable for one component and absent for another without grounds.
Return the recommendation, the whole consequence account, feasibility conditions and the decision-changing uncertainty to EAM.11 and EAM.12. EAM.13 later returns observations to the premise they affect. If a missing shared-work fact can change the choice, obtain it only when its attainable answer warrants the inquiry’s full burden. A project that remains locally useful can be deferred for a qualified portfolio reason without being relabelled technically poor.