The Flow Index

Which of the seven flows were binding constraints at the decisive phase of a program, scored against the public record, with a citation behind every cell.

Updated 2026-09-02 · 2 projects · 14 observations

Hover or tap a cell for the evidence behind it. Full notes and sources are listed under Evidence.

How to read it

Binding Binding constraint

The public record shows this flow was unavailable when the work wanted it, and that unavailability gated a stage or moved a date.

Fed Fed on demand

The public record positively shows this flow was supplied when the work wanted it. This is a stronger claim than silence, and the evidence note says what the record shows.

Not reported Not reported as binding

The public record does not identify this flow as gating the work at this phase. This is weaker than a claim that the flow was healthy. Absence of a finding is not a finding.

No record Insufficient public record

The public record does not say enough either way. Recorded as a gap rather than guessed.

The difference between "fed on demand" and "not reported as binding" carries most of the weight here. The first is a positive finding: the record says the flow was supplied. The second is silence: the record does not raise it, which is much weaker, because audit reports document what went wrong far more thoroughly than what went right. Collapsing the two would be the easiest way to make this index dishonest, and it would also erase the contrast it exists to show.

Method

A flow is recorded as a binding constraint when two conditions both hold in the public record: the flow was not available when the work wanted it, and that unavailability gated a stage or moved a published date. Inconvenience is not enough. A flow that was tight but never gated anything is not binding.

Each project is scored at a declared phase, not across its whole life. This matters: Crossrail's information flow was adequate during tunnelling and decisive at trial running. Scoring "Crossrail" as a whole would be meaningless, so the phase is part of the row.

Every cell carries a source. Where the record is silent the cell says so rather than guessing.

The seven flows, and a caveat about them

Information

Design decisions, approvals, responses to queries, assurance and acceptance documentation.

Materials

Components and materials present at the work face when the work wants them.

Labor

Crews of the required trade and skill, in the required quantity.

Equipment

Plant and tools available for the duration the work requires.

Workspace

Physical space available and free of competing work.

Precedence

Connecting or prerequisite work complete to the standard the next stage requires.

External conditions

Weather, permits, regulatory approval, utility connection, and other conditions outside the program.

This list follows Koskela's seven preconditions for a sound construction task1 as operationalized at Stanford's Center for Integrated Facility Engineering by Garcia-Lopez and Fischer.2 Formulations vary across the literature. Some substitute "work sequence" for "external conditions", others merge workspace into precedence. This index uses the list above consistently, and readers comparing it against another source should expect that difference.

A second caveat, stated plainly because it affects how much weight this table can carry: the categories are not fully orthogonal. An unanswered design query is both an information failure and a missing prerequisite. Where a single phenomenon could be filed under two flows, the evidence note says which and why.

Evidence

Crossrail Endgame, 2019 to 2020

Information Binding constraint

Roughly 200,000 assurance documents were needed to prove the railway safe, while pre-2019 management information tracked construction completeness rather than documentation completeness. A signalling update needed for trial operations ran three to eight weeks late and gated the stage behind it. National Audit Office (2021)

Materials Not reported as binding

Not identified as a constraint on the endgame in the audit record. National Audit Office (2021)

Labor Not reported as binding

Not identified as a constraint on the endgame in the audit record. National Audit Office (2021)

Equipment Not reported as binding

Not identified as a constraint on the endgame in the audit record. National Audit Office (2021)

Workspace Not reported as binding

Not identified as a constraint on the endgame in the audit record. National Audit Office (2021)

Precedence Binding constraint

The six stage testing ladder makes static proof an absolute precondition for dynamic testing. Stages could not be compressed or resequenced under schedule pressure. Crossrail Learning Legacy

External conditions Not reported as binding

Not identified as a constraint on the endgame in the audit record. National Audit Office (2021)

Huoshenshan hospital Whole build, 24 January to 3 February 2020

Information Fed on demand

The design adapted the existing Xiaotangshan standard plan from 2003, so design decisions and approvals were largely resolved before day one. GlobalData (2020)

Materials Fed on demand

Wards were prefabricated modules assembled before arriving on site and fitted out in parallel, off the critical path. GlobalData (2020)

Labor Fed on demand

Round the clock working under national mobilization. GlobalData (2020)

Equipment Fed on demand

35 excavators and ten bulldozers on site levelling alone. GlobalData (2020)

Workspace Fed on demand

Single greenfield site, one building, no competing trades or existing operations. GlobalData (2020)

Precedence Fed on demand

Modular assembly on a prepared slab. Prerequisite chains were short and largely parallel. GlobalData (2020)

External conditions Fed on demand

Permits and utility connections cleared by decree under emergency powers. GlobalData (2020)

Use the data

The index is published as CSV and JSON, one row per project and flow. Licensed CC BY 4.0: use it, including commercially, with attribution to Mimar.

Corrections

If a cell is wrong, or a source says something other than what is claimed here, write to contact@multisync.io. Corrections are made and noted. An index that cannot be corrected is a brochure.

by Ahmed Schrute