57 terms

P6 & scheduling glossary

The vocabulary of Primavera P6 and project scheduling, defined the way I would explain it on a call — short, plain, and honest about what each term is actually for. Product terms stay in English because P6 does; the definitions do not assume you already know them.

Structure & breakdown

# WBS Work Breakdown Structure

The hierarchical breakdown of a project's scope into manageable pieces. In P6 every activity lives under a WBS node, and most reporting rolls up through it.

# EPS Enterprise Project Structure

The organisation-wide hierarchy that projects sit in, above the project level — how an enterprise groups its projects by region, business unit or phase.

# OBS Organizational Breakdown Structure

The hierarchy of responsibility — who owns which part of the work — used in P6 to drive security and accountability.

# CBS Cost Breakdown Structure

The hierarchical breakdown of a project's cost — the money counterpart of the WBS. In P6 it is carried by Cost Accounts, a hierarchy you assign to activities and resource assignments so budget and actuals roll up by account.

# Activity

The smallest unit of work P6 schedules — a task with a duration, dates and logic. The building block of the network.

# Activity ID

The stable, user-facing code that identifies an activity (e.g. A1010). Unlike the internal database id, it does not change between exports.

# Milestone

A zero-duration activity marking a point in time — a start, a finish, a contractual gate. It carries no work, only a date.

# UDF User-Defined Field

A custom field you add to P6 to hold data the standard schema does not — a PO number, a review status, a risk tier.

# Activity Code

A tag you attach to activities to filter, group and report by — discipline, area, phase, contractor. The backbone of most useful layouts.

Activity types

# Task Dependent

The default activity type; its duration is driven by its own activity calendar. Most construction activities are Task Dependent. Related: Activity types explained →

# Resource Dependent

An activity whose dates are driven by the calendars of its assigned resources rather than its own — the least available resource can stretch the finish. Related: Activity types explained →

# Level of Effort LOE

An activity whose duration is defined by its relationships to other activities — supervision, project management — rather than discrete work. It spans whatever it is linked to. Related: Activity types explained →

# WBS Summary

An activity that summarises everything within its WBS branch, spanning the earliest start to the latest finish of that branch regardless of logic. Related: Activity types explained →

Logic & network

# Predecessor / Successor

The activities that come before and after a given activity in the network. Logic is expressed as these relationships.

# Relationship (FS / SS / FF / SF)

The four link types between activities — Finish-to-Start (the default and clearest), Start-to-Start, Finish-to-Finish, and Start-to-Finish (rare, usually a mistake).

# Lag

A delay applied to a relationship — a Finish-to-Start with a 5-day lag means the successor starts five days after the predecessor finishes. A lag has no owner or resources. Related: Check Schedule & the DCMA 14 →

# Lead

A negative lag — the successor starts before the predecessor finishes. Usually a Start-to-Start written badly. Related: Check Schedule & the DCMA 14 →

# Open End

An activity missing a predecessor or successor, disconnected from the network so a delay cannot propagate through it. Related: Check Schedule & the DCMA 14 →

# Critical Path

The chain of activities that determines the project finish date; delay any of them and the project slips. In P6, typically the path of zero (or least) total float.

# Longest Path

P6's definition of criticality based on the actual longest chain to the finish, rather than a total-float threshold — more reliable across multiple calendars and constraints.

# Out-of-Sequence

Progress recorded on an activity before its predecessor has finished, which breaks the assumed CPM logic. How P6 handles it depends on Retained Logic vs Progress Override.

# Retained Logic / Progress Override

The two ways P6 reschedules out-of-sequence work — Retained Logic keeps the remaining work waiting on the predecessor; Progress Override ignores the unfinished predecessor for the remainder.

Dates, durations & float

# Data Date

The "as of" date of a schedule update — everything left of it is actual, everything right is forecast. Moving it forward is how a schedule is progressed.

# Baseline

A frozen snapshot of the schedule at a point in time, kept as the reference the current plan is measured against.

# Original / Remaining Duration

The originally planned length of an activity, and how much is left as of the data date. They diverge once work starts.

# Total Float

The amount of time an activity can slip without delaying the project finish. Zero or negative total float marks the critical path.

# Free Float

The time an activity can slip without delaying its earliest successor — a subset of total float.

# Negative Float

The schedule saying a date cannot be met — the calculated late finish falls before the early finish, usually because of a constraint or imposed date. Related: Constraints in P6 →

# Constraint (hard / soft)

An instruction to hold a date regardless of logic. Soft constraints (Start On or After) let the network still react; hard constraints (Mandatory Finish) override it and hide delay. Related: Constraints in P6 →

Progress & calendars

# Percent Complete (Duration / Physical / Units)

The three ways P6 measures progress — Duration % (time elapsed), Physical % (a manual judgement of work done), Units % (resource units consumed). Choosing the wrong one is a common source of fiction in earned value. Related: Earned value in P6 →

# Calendar

The working-days-and-hours pattern P6 uses to convert durations into dates — shifts, weekends, holidays. Wrong calendars create phantom float and date anomalies.

Resources & cost

# Resource

The people, equipment or materials assigned to activities to carry cost and effort. A schedule with resources is "resource-loaded".

# Role

A skill or job type (planner, welder, crane) used to plan demand before named resources are known.

# Resource Loading

Assigning resources and costs to activities so the schedule also models who and how much — the basis of histograms and earned value.

# Resource Leveling

Adjusting the schedule so resource demand stays within availability, resolving over-allocation — often at the cost of the finish date.

# Over-allocation

A resource assigned more work in a period than it can do. Leveling or re-planning resolves it.

Earned value

# PV / BCWS Planned Value

The budgeted cost of the work scheduled to be done by the data date — what you planned to have earned. Related: Earned value in P6 →

# EV / BCWP Earned Value

The budgeted cost of the work actually completed — what you have genuinely earned. Related: Earned value in P6 →

# AC / ACWP Actual Cost

What the completed work actually cost. Related: Earned value in P6 →

# BAC Budget at Completion

The total budget for the project — the baseline cost of all the work. Related: Earned value in P6 →

# EAC Estimate at Completion

The forecast total cost given performance so far — what the project is now expected to cost. Related: Earned value in P6 →

# ETC Estimate to Complete

The forecast cost of the remaining work — EAC minus AC. Related: Earned value in P6 →

# VAC Variance at Completion

BAC minus EAC — how far over or under budget the project is forecast to land. Related: Earned value in P6 →

# SPI Schedule Performance Index

EV / PV — below 1.0 means less work done than planned. Related: Earned value in P6 →

# CPI Cost Performance Index

EV / AC — below 1.0 means the work cost more than it earned. Related: Earned value in P6 →

# TCPI To-Complete Performance Index

The cost efficiency the remaining work must hit to still meet the budget — a reality check on the EAC. Related: Earned value in P6 →

# BEI Baseline Execution Index

Tasks actually completed divided by tasks the baseline said should be complete by now — a DCMA measure of execution pace. Related: Check Schedule & the DCMA 14 →

# CPLI Critical Path Length Index

Whether the remaining critical path fits the time available; below 0.95 flags a schedule that no longer fits its end date. Related: Check Schedule & the DCMA 14 →

Quality, files & tools

# DCMA 14-Point Assessment

A schedule-quality checklist from the US Defense Contract Management Agency — fourteen mechanical checks (logic, float, constraints, BEI…) now used across industries. Related: Check Schedule & the DCMA 14 →

# Check Schedule / Schedule Log

P6's own report of what the last scheduling run did — how many activities carry constraints, negative float, or scheduled out of sequence. The cheapest quality report in the product. Related: Check Schedule & the DCMA 14 →

# XER

Primavera's tab-delimited text export format — the lingua franca of moving P6 data between databases and systems. Related: Inside the XER file →

# P6 Professional

The desktop P6 client — the powerful, install-on-Windows scheduling application. Related: Professional vs EPPM vs Cloud →

# P6 EPPM Enterprise Project Portfolio Management

The enterprise, web-based P6 — centralised database, role-based security, API access and portfolio views. Related: Professional vs EPPM vs Cloud →

# Oracle Primavera Cloud OPC

Oracle's newer cloud-hosted planning platform — a separate product from P6 EPPM rather than a hosted version of it. Related: Professional vs EPPM vs Cloud →

# BI Publisher

Oracle's reporting engine bundled with P6 for pixel-perfect, formal report output.

# Primavera Gateway

The integration product that syncs data between P6 and other Oracle systems such as Unifier and ERP.

# Primavera Unifier

Oracle's cost, contract and project-controls management platform, often paired with P6.