Fixed-Fee vs Time & Materials

Definition

Fixed-fee (FF) and Time & Materials (T&M) represent opposite ends of the risk spectrum in project pricing.

Fixed-fee shifts all execution risk to the agency. The client pays one price regardless of actual effort. If the project overruns, the agency absorbs the loss. FF requires accurate scope definition, historical data for estimation, and a change-order protocol. The agency benefits from efficiency gains but is exposed to scope creep.

T&M shifts risk to the client. The client pays for actual hours worked, so overruns directly increase the invoice. T&M protects agency margins on uncertain scopes but creates client distrust and incentivizes inefficiency (real or perceived). Most sophisticated buyers resist pure T&M for this reason.

Hybrid models are increasingly preferred: a fixed baseline scope with T&M for changes and overages, or a "not-to-exceed" cap on T&M engagements. ScopeMetrix's data shows that pure FF without risk premiums has a 30-40% probability of negative margin on complex projects, while hybrid approaches reduce this to under 10%.

The choice between FF and T&M should be deliberate and data-informed, not a default inherited from past practice.