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Estimating

What they are: The hours of effort each role puts into each activity, estimated as one figure or as a best, likely and worst case. As work is done, you record actual hours to compare against the estimate.

Example: The Design Engineer on "Detail Design" is estimated at 40 hours optimistic, 60 most likely and 110 pessimistic. The PERT estimate is (40 + 4 × 60 + 110) ÷ 6 = 65 hours. Once the work is done, 72 actual hours are recorded: a variance of +7 hours, over the estimate.

Key points:

  • Effort is in hours, set per role on each activity
  • A project uses single-point (one figure) or three-point (optimistic, most likely, pessimistic) estimates
  • In three-point projects the PERT value is the estimate everywhere in the app
  • Actual hours can be recorded in either mode, and are compared only with the work that has them
  • Guests and public links see estimates, never actual hours

Effort hours

Every role on an activity can carry hours of effort. Enter them in the activity's details in edit mode, under each role (see Activities). Hours save when you leave the field or press Enter.

These hours add up across the app: the Effort tab, Responsibilities, Staff Guide, the Activities tab cards, the Health Check and every export use the same figure for each assignment.

Single-point and three-point estimates

Choose the Estimation mode in the project's Settings, under Timing & Effort.

  • Single-point: one Hours figure per role. Simple and quick, and right when the work is well understood.
  • Three-point: three figures per role. O (optimistic) is the hours if things go well, M (most likely) is what you'd expect, and P (pessimistic) is the hours if things go badly. O can't be more than M, and M can't be more than P. Use this when the work is uncertain and you want the estimate to show it.

You can switch modes at any time without losing anything. Hours and O/M/P are both kept, and the activity shows the set for the current mode.

How PERT works

In a three-point project, each assignment's estimate is its PERT value:

PERT = (O + 4 × M + P) ÷ 6

This leans towards the most likely figure, but a long pessimistic tail pulls it up. That's why a PERT estimate is usually a little above M.

An assignment needs all three of O, M and P for PERT. If any is missing, its single-point Hours are used instead, so a half-finished estimate still counts.

The range: σ, P80 and P90

Three-point estimates also tell you how uncertain the total is. The Effort tab and the Estimation Report show:

  • Expected: the total of the PERT estimates
  • σ (sigma): the spread around that total. Each assignment's is (P − O) ÷ 6, and they combine across the project.
  • P80 and P90: the totals you'd stay within 80% and 90% of the time. Use P80 or P90 when you need a figure you can commit to with some confidence.

These assume the total follows a normal (bell-curve) distribution, so treat them as a guide rather than a guarantee. They only appear in three-point projects.

Actual hours

Each role on an activity also has an Actual field, in either estimation mode. Record the hours actually spent as the work is done. Actuals never change the estimate.

Variance and coverage

Switch the Effort tab to Actuals to compare actual hours with the estimate (see Project tabs). The Estimation Report shows the same comparison (see Offline copies).

  • Variance is actual minus estimate, counting only assignments that have actual hours. Work nobody has logged yet is left out, so unfinished work doesn't look like a saving. A positive variance means over the estimate and shows in red. A negative one means under.
  • Coverage is how much of the estimate those tracked assignments make up. Low coverage means the variance only tells you about a small part of the project so far.

Effort multiplier

The Effort multiplier, in the project's Settings under Timing & Effort, is how many hours one role has available per week or month, for example 38 hours per week. The Health Check uses it as each role's capacity: it flags a role whose estimated hours in a phase are more than the phase's length allows. Leave it empty and that check is skipped.

Who sees what

  • Authors enter and change hours, O/M/P and actual hours, in edit mode.
  • Project members (authors and reviewers) see estimates, the PERT range, actual hours and variance.
  • Guests and public links see the estimate and PERT range, but never actual hours: not on activities, and the Effort tab has no Actuals view for them.