The Researcher's Tool Kit

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Percent Effort_Person Months conversions made easy

Making a budget request in a grant proposal?  Submitting a progress report?  Confirming commitments for other support?

If so, you may need to calculate effort on a project in terms of a percentage and/or person months.  This seems like it should be a quick process until one realizes conversions are dependent upon appointment type (calendar year, academic year, summer months) AND not all persons included on your project may have the same type of appointment or are employed by the same institution.  What to do?  Many calculators and tables are available to assist you in this process.  I suggest using the PercentEffortConversionTable to make calculations quickly and accurately (thanks to Aparna Menon, Financial Specialist from the Institute for Molecular Engineering at the University of Chicago for sharing this resource).  Read below for more detailed information to support your use of the provided conversion tool.tool kit

What is the definition of person months?
Per NIH, “Person months is the metric for expressing the effort (amount of time) PI(s), faculty and other senior personnel devote to a specific project. The effort is based on the type of appointment of the individual with the organization; e.g., calendar year (CY), academic year (AY), and/or summer term (SM); and the organization’s definition of such. For instance, some institutions define the academic year as a 9-month appointment while others define it as a 10-month appointment.”

How do you calculate person months?  Use PercentEffortConversionTable; however, here’s the rationale for those calculations.
Per NIH, “Conversion of percentage of effort to person months is straight-forward. To calculate person months, multiply the percentage of your effort associated with the project times the number of months of your appointment. For example:

  • 25% of a 9 month academic year appointment equals 2.25 (AY) person months (9 x 0.25= 2.25)
  • 10% of a 12 month calendar appointment equals 1.2 (CY) person months (12 x 0.10 = 1.2)
  • 35% of a 3 month summer term appointment equals 1.05 (SM) person months (3 x 0.35= 1.05)
  • 10% of a 0.5 FTE 12 month appointment equals 0.6 (CY) person months (12 x .5 X .1 = 0.6)

Another example:  If the regular pay schedule of an institution is a 9 month academic year and the PI will devote 9 months at 30% time/effort and 3 months summer term at 30% time/effort to the project, then 2.7 academic months and .9 summer months should be listed in the academic and summer term blocks of the application (9 x 30% = 2.7 person months; 3 x 30%= .9)”

Why should I care about percent effort?

Funding agency staff review budget justifications and other support statements to determine if any personnel supported on a project exceed 12 person months of funding per year. Personnel with over 12 person months of support may indicate over- commitment of available effort for your project and risk continued financial support.