3.4 Estimating effort and calendar time

The first attempt is only one part of the work. A more complete estimate is:

\[ \text{Planned effort} =\text{production} +\text{verification} +\text{revision} +\text{integration} +\text{contingency}. \]

Here, production is the time required to create the first complete version. Verification includes checking data, formulas, code, outputs, and interpretation. Revision includes changes after review. Integration includes reconciling the work with other analyses and deliverables. Contingency is a reasonable allowance for uncertainty.

Planned effort should be expressed in person-hours. Calendar time is different because a four-hour task may take several days to complete if it depends on a response, approval, file transfer, software installation, or teammate review.

Worked Example: Estimating an EDA Section

Suppose a team estimates the following:

• initial summaries and figures: 6 hours;
• data-quality verification: 3 hours;
• peer review and corrections: 3 hours;
• integration with the dictionary and report: 2 hours;
• contingency for unexpected data issues: 2 hours.

The planned effort is

\[ 6+3+3+2+2=16\text{ person-hours}. \]

If two people can work independently on parts of the analysis, the calendar time may be shorter than 16 hours. If both people need access to a definition from the client before proceeding, the calendar time may be longer. The schedule should record both effort and waiting dependencies.