Glossary

Scheduling & claims terms, explained.

Plain-language definitions of the construction scheduling and delay-claim concepts Claims Digger works with every day.

56 terms

Scheduling Fundamentals

Construction Schedule: A construction schedule is the planned sequence and timing of every activity needed to complete a project, showing what work happens when, in what order, and how each task depends on the ones before and after it.
Critical Path: The critical path is the sequence of connected activities in a schedule that determines the project's earliest possible finish date -- any delay to an activity on it delays the whole project by the same amount.
Total Float: Total float is the amount of time an activity can be delayed without pushing back the project's overall finish date.
Baseline Schedule: The baseline schedule is the originally approved project schedule, used as the fixed reference point every later update is measured against to identify delay.
Data Date: The data date is the 'as of' date a schedule update reflects -- everything before it is treated as actual progress, everything after it is forecast.
Free Float: Free float is how long an activity can slip before it delays the very next activity, as opposed to total float, which measures how long it can slip before it delays the project finish.
Relationship Types (FS, SS, FF, SF): Relationship types define how one activity depends on another: Finish-to-Start, Start-to-Start, Finish-to-Finish, and Start-to-Finish, each linking the two activities' dates differently.
Lag and Lead: Lag adds a waiting period between two linked activities; lead (negative lag) does the opposite, letting the successor start before its predecessor has actually finished.
Longest Path: Longest path is an alternative definition of 'critical' -- the single longest continuous chain of logically-tied activities from start to finish -- which P6 lets a project use instead of the more common zero-float definition.
Work Breakdown Structure (WBS): The Work Breakdown Structure is the hierarchical breakdown of a project into phases, areas, or systems -- Sitework, Foundations, Structural Steel -- that every activity belongs to.
Critical Path Method (CPM): The Critical Path Method is the scheduling technique that calculates each activity's earliest and latest possible dates from durations and logic, and identifies the longest chain of dependent activities that determines the project's finish date.
Milestone: A milestone is a zero-duration schedule activity that marks a point in time, such as a contractual date or the completion of a phase, rather than a piece of work.
Schedule Update: A schedule update is a periodic revision of the project schedule that records actual progress up to a data date and re-forecasts the remaining work.

Claims & Delay Analysis

Schedule Delay Claim: A schedule delay claim is a request for additional time (and often money) based on documented evidence that specific events pushed back a project's completion date beyond what the contract allows without penalty.
Time Impact Analysis (TIA): A Time Impact Analysis is a forensic scheduling method that inserts a delay event as a fragnet into the schedule at the time it occurred, to measure exactly how much it pushed back the project finish date.
Concurrent Delay: Concurrent delay occurs when two or more independent delay events -- typically one caused by the owner and one caused by the contractor -- affect the critical path at the same time, complicating who is entitled to time and money.
As-Built Schedule: An as-built schedule is a record of what actually happened on the project -- the real start and finish dates of the work -- as opposed to what was planned.
Constructive Acceleration: Constructive acceleration is a claim theory in which a contractor that was entitled to a time extension, but was refused it, speeds up the work to meet the original date and seeks the cost of doing so.
Recovery Schedule: A recovery schedule is a revised schedule that shows how a contractor plans to regain time lost to delay and finish by a required date.
Disruption: Disruption is interference that makes work less productive or more costly without necessarily delaying the project's completion date.

Schedule Quality

DCMA 14-Point Assessment: The DCMA 14-Point Assessment is a standardized set of 14 checks -- developed by the Defense Contract Management Agency -- used to evaluate whether a project schedule is well-built enough to be trusted for forecasting and delay analysis.
CPLI (Critical Path Length Index): CPLI measures whether a project's critical path is getting longer relative to baseline, calculated as (Critical Path Length + Total Float) / Critical Path Length.
BEI (Baseline Execution Index): BEI measures execution against plan: of all the activities the baseline expected to be finished by today's data date, what fraction actually are.
Hard Constraint: A hard constraint pins an activity to a fixed date -- Mandatory Start or Mandatory Finish -- overriding the logic-driven dates the schedule would otherwise calculate.

Schedule Mechanics & Data

XER File: An .xer file is Primavera P6's plain-text, tab-delimited export format -- a stack of separate tables (activities, relationships, calendars, and more) rather than a single flat file.
EPS (Enterprise Project Structure): The EPS is P6's top-level hierarchy for organizing multiple projects -- by division, region, or program -- above the level of any single project's own Work Breakdown Structure.
Fragnet: A fragnet is a small fragmentary network of activities representing a specific delay event, inserted into a schedule to model that event's impact on the project finish date.
Out-of-Sequence Progress: Out-of-sequence progress is when an activity is reported as started or complete before its predecessor's logic says it should be possible -- a sign the schedule's logic doesn't match how the work actually happened.
Open End: An open end is an activity in the middle of a schedule with no predecessor, no successor, or both -- a logic gap that keeps it from being properly tied into the calculated network.
Contemporaneous Critical Path: The contemporaneous critical path is whichever chain of activities was actually driving the project's finish date at a specific point in time -- as opposed to whatever the original baseline predicted it would be.
Near-Critical Activity: A near-critical activity has low but positive total float -- close enough to zero that a small additional delay would push it onto the critical path.
Float Erosion: Float erosion is a steady decline in an activity's total float across consecutive schedule updates -- a trend that can signal a project heading toward trouble well before any single update looks alarming on its own.
Negative Float: Negative float means an activity's late dates are calculated as earlier than its early dates -- a sign the schedule's own logic already shows the project finishing later than a required or contractual date.
Activity ID Reuse: P6's internal activity ID (task_id) can differ between two exports of what a human would call the same schedule -- which is why schedule comparison tools match activities by their human-readable Activity ID (task_code) instead.
Retained Logic: Retained Logic is a Primavera P6 scheduling option under which the remaining work of an out-of-sequence activity still waits for its predecessors to finish.
Progress Override: Progress Override is a Primavera P6 scheduling option under which the remaining work of an out-of-sequence activity ignores its unfinished predecessors and continues from the data date.

Delay Analysis Methods

Windows Analysis (Time Slice Analysis): Windows analysis divides a project's timeline into consecutive periods -- usually matching real schedule updates -- and separately identifies what was driving the critical path and how many delay days occurred within each one.
Collapsed As-Built: Collapsed As-Built (CAB) removes a specific delay event from the real as-built schedule record and re-links the network around the gap, comparing the resulting hypothetical finish date to what actually happened.
Impacted As-Planned: Impacted As-Planned (IAP) inserts a delay-event fragnet directly into the original, unprogressed baseline schedule and recalculates -- simpler than Time Impact Analysis, but criticized for ignoring how the project actually progressed before the event.
As-Planned vs. As-Built: A direct comparison of planned dates against actual dates -- the simplest retrospective delay technique, but one that can't by itself distinguish real delay from an activity's slippage simply being absorbed by its own float.
But-For Delay: But-for delay analysis reconstructs a project without one specific delay event to isolate how much later the project finished because of that event alone.
Measured Mile: Measured mile analysis quantifies lost labor productivity by comparing the actual production rate achieved during an unimpacted period of work against the rate achieved during a disrupted period, using the project's own real data for both.
Pacing Delay: Pacing delay is a deliberate slowdown of one's own work on a non-critical path, made in direct response to an already-existing excusable delay caused by the other party, to avoid finishing far ahead of a schedule the other party has already delayed.
Total Time Method: The Total Time Method simply attributes the entire difference between the planned and actual completion dates to the party against whom the claim is made, without analyzing individual delay events -- widely regarded as the weakest and least defensible delay methodology.

Delay Classification & Claims

Excusable Delay: An excusable delay is one caused by circumstances outside the contractor's control or fault, entitling it to a time extension -- though not necessarily to additional compensation.
Compensable Delay: A compensable delay entitles the contractor to both additional time and additional money -- typically reserved for delays caused by the owner or the owner's own agents.
Non-Excusable Delay: A non-excusable delay is caused by the contractor's own fault or within its own control -- entitling it to neither a time extension nor additional compensation, and potentially exposing it to liquidated damages.
Extension of Time (EOT): An extension of time is additional contract time granted to a contractor, typically in response to an excusable delay, moving the required completion date without necessarily involving additional payment.
Apportionment: Apportionment is dividing responsibility for a delay period among multiple contributing causes -- most commonly needed when a concurrent delay has both an excusable and a non-excusable component.
Loss of Productivity (Disruption) Claim: A loss of productivity (or disruption) claim seeks compensation for reduced labor efficiency caused by a disruptive event -- distinct from a schedule delay claim, since a project can be disrupted without necessarily finishing late.

Standards & Frameworks

AACE RP 29R-03: AACE International's Recommended Practice 29R-03, "Forensic Schedule Analysis," classifies delay-analysis methods by a structured set of practical questions -- timing, data availability, and whether the goal is modeling or observation -- rather than prescribing one preferred technique.
SCL Delay and Disruption Protocol: The Society of Construction Law's Delay and Disruption Protocol is widely cited guidance offering a common vocabulary and a set of recognized delay-analysis methods -- not a binding rule unless a contract expressly incorporates it.

Earned Value / Metrics

BCWS (Budgeted Cost of Work Scheduled): BCWS, also called Planned Value (PV), is the budgeted cost of the work that was scheduled to be done by a given point in time -- one of the three base Earned Value Management measures.
BCWP (Budgeted Cost of Work Performed): BCWP, also called Earned Value (EV), is the budgeted cost of the work actually completed by a given point in time -- the core measure of how much progress has genuinely been earned.
ACWP (Actual Cost of Work Performed): ACWP, also called Actual Cost (AC), is what was genuinely spent to accomplish the work actually completed so far -- the real-dollar counterpart to the budgeted BCWP figure.
SPI (Schedule Performance Index): SPI = EV / PV (Earned Value divided by Planned Value) -- a cost-based measure of schedule performance, above 1.0 meaning ahead of schedule and below 1.0 meaning behind, that is not the same thing as a CPM-based metric like CPLI or float.