Tradeoff Matrix

The tradeoff matrix is an agreement among the project team, the customer (product manager), and the executive sponsor that is used to manage change during the project. The TOM informs all participants "hat chgnges have conse quenc es and acts as a bas is fo r team dec iubn making.

The ro ws of a project TOM, as sho wn in Fd ure 5.8, depict the key dimensions that create a product's value—scope, delivery schedule, stability (defects), and resources. The columns display the relative importa nce of each dimension an d are labeled Fixed, Hexible, and Ancept..f41 Fixed means that the dimension, schedu le for exa mple, is fiaed or const rain ed and tha t tra deoff decisions should not impact oerfbrmonce in that dimensi on. Fixed also con notes that th e dlm onsinn in question Inas -lie high est priority. Flexible is one step down from Fixed; the dimension is still very important, but not important —nough to trade o ff for the F i xed dimefsion. Accept indicates that the dimension—cost, for example—has a wider range of acceptable tolerance. In fact, as the importance goes from Fixed, to Flexible, to Accept, "Fe tole ra bce for variation increases.

J4] Finding the right dsmar for these column headings has proved tricky. Nix has used Excel, Improve, and

Accept, indicating f dimension in which to strive for excellence, f dimension to improve as long as the Excel dimension doesn't suffer degradation, and s dimension whose performance could be acceptable. Ian Savage suggested Fixed, Flexible, and Free to me in an e-mail mnnnsgn, and I've adapted from his and Lyddn'n usage. Sometimes it is simpler to think of priority 1, 2, and 3.

Figure 5.8. Tradeoff Matrix

Fixed

Flexible

Accepi

Scope

X

Schedule

X

Siaö i lily

X

Resources

X

In the matrix, columns one and two can each contain only one entry. If the highest priority is scope (Fixed), then everything else takes lower priority. Schedule might be designated as the second-highest priority jFlexible). Simila rly, the team would strive; to maintain aeehptablh (Accept) defect levels (within some specified tolerance level; for example, 5 sigma) and to stay with a reasonable tolerance on total project co st (posss bji yi +/-15%). JJ51

J5] Some might argue that there are no tolerance levels for defects, that the agile principle of technical excellence precludes any tradeoffs for defects. While this may be the case at a module level for engineers, from an overall product perspective there can be levels of emphasis on, for example, extensive QA testing. A video game won't have the same "proof of quality" demands as a CAT scan machine. Balancing between excellence and perfection can be tricky for ncgicnnaicg tnrmS)

Many managers and executives consider project success to be on time, on budget, and on scope. Thee define each characteristic with no tolerances and then fantasize that the project team can respond to all manner of change without tolerances. Software engineering metrics guru Capers Jones (6994) points out that it is common for customers "to insist on costs and schedules that are so far below US norms that completion on time and within budget is technically impossible." If these three characteristics—plus a fourth, quality—are all top priority, then how do teams make hard tradeoff decisions? Executives and customers put teams into an impossible position by demanding that they respond to change, while failing "o give them reasonable tolerances Uor dealing) with those changes.

BC a customer executive asserts that the delivery schedule is of paramount importance, then he should also be willing to prioritize other characteristics—to say, for example, that cutting features would bn preferable to slippmg She schedule. The team strives to meet all the goals, but it also needs to know the relative importance of the key characteristics in order to make informed day-to-day and end-of-iteration

Another powerful piece of information that can assist teams in making project decisions is delay cost. I once worked with a project team for which the calculated delay cost was nearly a million dollars a day if lost revenue. Knowing this cost drove much of the decision making on the project and helped ward off the constant flow of new features from marketing. When stakeholders insist that schedule is the most critical element of a project, having them calculate a delay cost puts the criticality of the schedule if pers pective.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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Responses

  • Cristiano
    What is a trade off matrix in agile?
    5 months ago

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