Start with the event and the right schedule.
AACE Recommended Practice 52R-06 describes prospective TIA as a forward-looking method: model an event in a schedule representing progress just before it, then assess the effect on completion. It is guidance, not a universal standard.
The SCL Delay and Disruption Protocol highlights the importance of schedules, records and timely assessment. The right method depends on the circumstances; one calculation cannot settle every delay question.
| Review principle | Girdero’s support |
|---|---|
| Use a suitable starting schedule | Explicit source roles and date comparisons; the reviewer checks the progress basis. |
| Examine the event’s work and connections | Added-activity evidence and relationship checks. |
| Assess the change in completion | Selected-target finish movement and a separate day-level estimate. |
| Keep the assessment supported | Review notes, optional attachments and saved history. |
Three files, three clear roles.
In Girdero, select the files used for the event analysis. Their contents and assigned roles matter more than their filenames.
| File role | Simple meaning |
|---|---|
| Unimpacted schedule | The plan before this event is added. |
| Impacted schedule | The recalculated plan with the event included. |
| Fragnet | The small group of activities and connections representing the event. |
These should form a matching set for the same analysis. An unrelated starting file can introduce hundreds of differences that have nothing to do with the event.
The reviewer also checks whether the starting schedule accurately reflects progress before the event. The data date is the date up to which progress is recorded. Having the same data date does not prove that the files are suitable.
Put the event in context. Choose the finish to measure.
Extra work affects completion through its connections to other work. In this example, project completion waits for new handover documentation after inspections.
Girdero reads those connections from the files. Selecting A720 tells the app which finish to measure; it does not create or move the extra work. A720 is simply the code in this example, not an industry-required activity code.
Projects can have several finish milestones, such as basement completion, building handover and overall completion. Girdero can show supported milestone comparisons alongside the main target.
Extra work does not always delay final completion. It may have spare time available or affect work that does not control the project finish.
Check the comparison before trusting the number.
AACE’s insertion procedure includes testing the inserted work with zero duration before evaluating its duration-driven effect. Girdero provides a day-level version of that check, together with other input comparisons. [1]
| Girdero check | What it helps you inspect |
|---|---|
| Schedule dates | Whether the files share a data date. |
| Added work & connections | Expected inserted activities, their ties and unexpected changes to existing work. |
| Working calendars | Supported working-time definitions, including working days and exceptions. |
| Zero-duration insertion | Whether inserting the event with no duration still changes existing activity dates. |
| Scheduler date reproduction | Whether corresponding file dates and app results agree. Completed actual dates are checked for preservation. |
| Budget comparison | Whether budgeted cost changed. This is context, not proof of time impact. |
| Recorded contract deadline | Whether the file’s deadline can be compared with the approved-date ledger. |
| Finish versus deadline | Where the resulting finish falls relative to the filed deadline. |
Open Details to see the values behind a check. A pass applies to that check’s scope. “Missing information” asks for supporting data; “Not computed” means no usable result was produced. It does not mean zero delay.
Separate the recorded movement from the estimate.
The difference between the target’s before-and-after finish dates.
A separate result using supported durations, relationships, calendars and progress information.
In the example, inspections finish on 18 November. Documentation occupies the next two working days, 19–20 November, and the completion milestone follows it. The filed finish moves from 18 to 20 November: two calendar days later.
If the independent estimate also shows two days, the results agree for this comparison. Agreement does not establish every assumption or reproduce all settings of a native scheduler such as Primavera P6.
The milestone table can display calendar days or working days. Calendar days include every day; working days follow the milestone’s calendar. The two numbers can match when there are no non-working days between the dates.
Keep the evidence with the decision.
SCL guidance gives records an important role in assessing delay. In practice, these can include instructions, progress reports, correspondence and scheduling records that support the event explanation. [2]
Girdero’s Review tab organises the assessment into submission, event and fragnet, starting schedule, impacted schedule, critical path and impact, and concurrency and responsibility.
- Formatted notes: record what was checked and what was found.
- Optional supporting files: attach PDF, Word, Excel or text evidence.
- Review checks: prompt for notes and confirmation before advancing through completed sections.
- Decision fields: record responsibility, overlapping delays, the assessment, decided days and reasons.
- History: retain saved reviews and their supporting evidence.
Concurrency means other delays may have affected completion at the same time. Recording a selection does not calculate or prove their effect; the reviewer must assess the evidence.
A new TIA revision retains the previous analysis. Saving a review records the assessment without changing its saved calculation.
From an event to a reviewable result.
- Describe what happened. Record the event and its date.
- Select the matching files. Check the unimpacted, impacted and fragnet roles.
- Confirm the target. Choose the completion activity relevant to the analysis.
- Inspect the checks. Resolve or explain unexpected changes and unavailable results.
- Read both results. Compare filed movement with the independent estimate and relevant milestones.
- Review and save. Record evidence, responsibility and the decision; use a new revision when the analysis changes.
The result is a documented event comparison that a reviewer can inspect, question and explain.
Sources
- AACE 52R-06: Prospective Time Impact AnalysisRevision dated 4 May 2017 · Purpose, overview and specification. Recommended guidance for prospective analysis.
- SCL: Delay and Disruption Protocol, second editionFebruary 2017 · Core Principles 1, 4, 5 and 10, and guidance on time impact analysis.
Product descriptions reflect the implementation reviewed for this article. The worked example is illustrative; it is not a certification of an analysis.