Report #86 metric. The number of months an agency requires to transition a federal program from one prime contractor to another without service disruption. Empirically tested at CMS in 2023-2024: when CMS attempted to enforce a Labor Harmony Agreement via early recompete of the $6.6 billion 1-800-MEDICARE contract, Maximus filed suit in the U.S. Court of Federal Claims; CMS withdrew the rebid by November 2024 — proving substitutability friction >24 months at the keystone. Engine values: Aidvantage 18-24mo (system novation + platform integration); VA MDE 12-18mo (4-incumbent oligopoly already exists on IDIQ vehicle); IRS / USCIS contact centers <12mo (multi-award task order competition / GSA Schedule rebids). Engine framing: substitutability friction is the load-bearing variable in the structural-recurrence pattern — it is what converts an outsourced contract into an entrenched federal-services substrate. When friction exceeds 24 months at scale, the federal government becomes operationally hostage to its own contractor.