FAQ

Questions, answered plainly.

Epoch SRA is an Excel add-in that runs calibrated Monte Carlo schedule risk analysis in Excel. Everything below describes shipped behavior. The name is written “Epoch SRA”; the one-word “EpochSRA” – as in epochsra.com – is the same product.

What is schedule risk analysis?

Schedule risk analysis (SRA) is the practice of treating a project schedule as uncertain and computing the range of finish dates it could actually produce, usually with Monte Carlo simulation. Instead of one deterministic finish date, SRA gives probability-tagged dates such as P50 and P80, so commitments can be made at a known confidence level.

What is a P80 date?

A P80 date is the date that 80% of simulated project outcomes finish on or before, leaving a 20% chance of finishing later. Epoch SRA treats P80 as the commitment level: its P80 is field-calibrated against replayed historical program actuals, while P50 is the median and deliberately styled as a reference, not a commitment.

What is merge bias?

Merge bias is the effect where a milestone fed by several parallel paths tends to finish later than any single path predicts, because the milestone must wait for the slowest path in each simulated outcome. It is a structural property of networks that deterministic schedules systematically understate, and one of the main reasons Monte Carlo dates are later than CPM dates.

How is Epoch SRA different from Full Monte?

Both tools run Monte Carlo schedule risk analysis. Epoch SRA runs as a task-pane add-in inside Excel, imports MS Project XML with the file's stored dates as the baseline, and prices risks from per-category impact priors that were field-calibrated against replayed historical space-program actuals, rather than asking the user to hand-estimate a distribution for every task. It also keeps a living loop: occurred events are logged as schedule mutations, believed versus actual magnitudes are recorded, and every run is seeded and reproducible. The full comparison states plainly where each tool is stronger.

What are alternatives to Full Monte?

Full Monte runs inside Microsoft Project; the main alternatives are Primavera Risk Analysis and Safran Risk at the enterprise end, RiskyProject as an affordable standalone desktop tool, and Epoch SRA if you want the analysis in Excel – on your MS Project XML, with field-calibrated priors and published pricing. Each is a different bet on where the work happens; the Full Monte alternative page and the master comparison table lay out the published facts side by side.

Is there a low-cost alternative to Primavera Risk Analysis?

Yes. Primavera Risk Analysis itself is quote-based enterprise licensing, but RiskyProject publishes prices at $685–$979 per year and is a capable standalone tool, and Epoch SRA is €119/month or €990/year, Excel-native, with a 7-day trial that needs no sales call. If your plans are in MS Project and your register is in Excel, the Primavera Risk Analysis comparison covers the trade-offs honestly, and the decision guide answers it in two lists.

Can @RISK do schedule risk analysis?

Yes – through its ScheduleRiskAnalysis (SRA) toolset, which imports Microsoft Project and Primavera P6 schedules into Excel for Monte Carlo analysis with probabilistic Gantt views. (Corrected 2026-08-06: an earlier answer here said percentile dates required hand-building the network in formulas – that understated the SRA toolset.) The differences are elsewhere: Epoch SRA prices risks from field-calibrated priors with every percentile labelled by provenance, refuses-and-reports anything its import cannot faithfully translate, runs DCMA-style schedule checks on every Compute, and publishes per-seat prices with a no-contact trial. See Epoch SRA vs @RISK ScheduleRiskAnalysis.

Is there a Lumivero schedule risk analysis product?

Yes. Corrected 2026-08-06: an earlier version of this answer wrongly said no standalone product of that name exists – that was our error, and this note stays up. Lumivero ScheduleRiskAnalysis (SRA) is a toolset within @RISK, shipped as part of the DecisionTools Suite, that imports Microsoft Project and Primavera P6 schedules into Excel and runs Monte Carlo on them, reporting results as standard and probabilistic Gantt charts with critical-path indices and a schedule audit report. Lumivero (formerly Palisade) has also acquired Risk Decisions, maker of the Predict! risk suite. For how it compares with Epoch SRA – local-only computation, calibrated priors with provenance, refuse-and-report import, published pricing – see Epoch SRA vs @RISK ScheduleRiskAnalysis.

Does Epoch SRA do cost risk?

Yes, since v1.1.0 (August 2026). Give tasks an optional cost_per_day (burn rate per working day of simulated duration) and fixed_cost, and risks an optional cost_impact (money added when the risk fires). Each simulated future then prices its own cost from the same draw that produced its dates – no new sampling, and schedule results stay bit-identical. You get cost P50/P80, a cost histogram, per-risk cost contribution on the tornado, and a delay price: the expected cost per week of finish slip past P50, measured across the run’s simulated futures at your rates. One honesty rule governs all of it: cost numbers are derived from the calibrated schedule simulation through your rates – rates are yours, distributions are the schedule’s – and cost percentiles are never labelled field-calibrated, because the backtest claim does not extend to money. The guide’s cost section documents the columns.

Does Epoch SRA import Microsoft Project files?

Yes. Export your plan from MS Project as XML (File > Save As > type: XML) and import it in the pane; the file is read locally and never modified. The import reproduces the file's stored dates as the baseline, translates all four link types (FS, SS, FF, SF) with working-day lags including leads, re-anchors summary links to leaf tasks, and is refreshable: re-importing keeps task ids stable by the file's own UIDs so risk mappings survive. Percent and elapsed-time lags have no exact working-day equivalent and are reported by name instead of approximated.

Does Epoch SRA run DCMA 14-point checks?

Eight of the fourteen – and it says which. Every Compute runs schedule quality checks aligned with the DCMA 14-Point Assessment, evaluating the eight points that schedule structure and a CPM pass can judge: logic (missing predecessors/successors), leads, lags, relationship types, high float, negative float, high duration, and the critical-path test. The remaining six – hard constraints, invalid dates, resources, missed tasks, CPLI, and BEI – need baseline, status, or resource data the add-in does not model, and each reports not applicable by name rather than a misleading pass. The results land in a “Schedule quality (DCMA-style)” section in the pane and in ESRA_Results. The checks are also informed by GAO Schedule Assessment Guide and NASA Schedule Management Handbook practices; no agency has reviewed or approved the product, and no such claim is made. The guide lists every point, implemented and not.

Can I use a normal/Gaussian distribution?

No, and the omission is deliberate. A normal distribution is symmetric and unbounded, so it puts real probability below zero – which in a schedule means a risk that fires and finishes the work early. Truncating it at zero would not fix that: cutting the tail moves the mean and every percentile away from the numbers you were shown, so the tool would display one distribution and simulate another. It also throws away the asymmetry a three-point estimate exists to express.

If what you want is the bell shape, pick Lognormal (bell shape, floored at zero) in the distribution selector. It is the same intent with the right support: a rounded body, a floor at zero that no draw can cross, and a right tail that runs past your maximum – which is usually why people reach for a bell in the first place. The guide’s “Choosing a distribution” section covers all four families. Distribution choice is an override: leave the column blank and the calibrated triangular prior is used, exactly as before.

Which calendar does Epoch SRA use?

Your file’s. Since v1.2.0 the MS Project import reads the file’s project calendar – working weekdays (5-day, 6-day, 7-day, whatever the file defines), day length, and holiday/extra-day exceptions within the schedule’s span – and that calendar drives duration counting, lag conversion, every computed date, and what “per week” means in the cost module’s delay price. It lands in an editable ESRA_Calendar sheet; workbooks built by hand get the same sheet with a Mon–Fri default. The file wins whenever a file exists: a re-import overwrites the sheet. A stored date is flagged only when it is non-working under the file’s own calendar – a genuine anomaly – not under an assumed workweek. Per-task calendar assignments are not simulated; each is reported by name and runs on the project calendar. The guide’s import section has the details.

What does Epoch SRA cost?

Three plans, per named user, ex-VAT: monthly at €119 per seat per month, annual at €990 per seat per year, and perpetual at €1,300 per seat plus €350 per year maintenance (€1,650 the first year, billed together). Every plan starts with a free 7-day trial in the add-in, and license keys are delivered by email within 24 hours of purchase.

How does the 7-day trial work?

The trial is full-featured and starts on your first Compute – no signup, no card. After 7 days Compute is disabled but your workbooks, imports, and previously computed results stay fully accessible; entering a license key restores full function immediately.

Is Epoch SRA only for space projects?

No. Epoch SRA is built from space-program experience and shaped for it – the risk taxonomy covers export-control delays, GFE deliveries, test failure and retest, and NCR/waiver loops, and the impact priors were calibrated against historical space-program schedules – so it is schedule risk analysis for space programs first. But the mechanics generalize: any program planned in MS Project or Excel with a costly finish date fits, and every category and prior is user-overridable per item.

Who is Epoch SRA for – and who is it not for?

For planning engineers, schedulers, project controls managers, risk analysts, SRA consultants, and program managers who defend milestone dates. Not for simple task tracking, Kanban or sprint teams, or projects without a network schedule – those are good ways of working that do not need this instrument. The honest split, in two lists: Who Epoch SRA is for.

Should I choose Epoch SRA or Primavera Risk Analysis?

Choose Primavera Risk Analysis if you are standardized on Oracle Primavera, need enterprise risk workflows integrated with P6, and have dedicated risk analysts. Choose Epoch SRA if your schedules live in MS Project and Excel, you want a forecast this week without a deployment project, and the person in the chair is the PM or planner. Both run Monte Carlo; the difference is where your schedule lives and who operates the tool. The full guide: Choosing between Epoch SRA and Primavera Risk Analysis.

Can I use my own risk categories?

Yes. The register has two columns since v1.0.5.0: category is yours – free text, any taxonomy your program already uses ("Payload thermal", "Customer ICD churn"), never validated, preserved verbatim through import and re-import. prior_class is separate: a dropdown of the eight calibrated failure patterns that picks which field-calibrated statistics price the risk. Your categories organize; prior_class computes. A risk without a prior_class is reported by name at compute, never guessed. The guide's register section has the full reference.

What does ECSS-style 5×5 mean here?

ECSS-M-ST-80 is the European space standard for project risk management; its scoring convention is a 5×5 grid – likelihood 1–5 times severity 1–5, giving a banded risk index of 1–25. Epoch SRA's register uses that convention, and the scored likelihood and severity are what price each risk's impact in the simulation. The guide glossary has the full definition.