DESIGN FOR SIX SIGMA (DFSS) TEAM AND TEAM SOFTWARE PROCESS (TSP) - Software Design for Six-Sigma: A Roadmap for Excellence - page 282

PROBE Calculation Worksheet Instructions

Purpose Use this form with the PROBE method to make size and

resource estimate calculations.

General - The PROBE method can be used for many kinds of

estimates. Where development time correlates with added
and modified size
- use the Added and Modified Calculation Worksheet
- enter the resulting estimates in the Project Plan Summary
- enter the projected added and modified value (P) in the
added and modified plan space in the Project Plan
Summary
- If development time correlates with some other
combination of size-accounting types
- define and use a new PROBE Calculation Worksheet
- enter the resulting estimates in the Project Plan Summary
- use the selected combination of size accounting types to
calculated the projected size value (P)
- enter this P value in the Project Plan Summary for the
appropriate plan size for the size-accounting types being
used

PROBE Calculations: Size
(Added and Modified)

- Added Size (A): Total the added base code (BA) and Parts
Additions (PA) to get Added Size (A).
- Estimated Proxy Size (E): Total the added (A) and
modified (M) sizes and enter as (E).
- PROBE Estimating Basis Used: Analyze the available
historical data and select the appropriate PROBE
estimating basis (A, B, C, or D).
- Correlation: If PROBE estimating basis A or B is selected,
enter the correlation value (R 2 ) for both size and time.
- Regression Parameters: Follow the procedure in the
PROBE script to calculate the size and time regression
parameters ( β 0 and β 1 ), and enter them in the indicated
fields.
- Projected Added and Modified Size (P): Using the size
regression parameters and estimated proxy size (E),
calculate the projected added and modified size (P) as P =
β 0 Size + β 1 Size * E.
- Estimated Total Size (T): Calculate the estimated total
size as T = P + B − D − M + R.
- Estimated Total New Reusable (NR): Total and enter the
new reusable items marked with * .

PROBE Calculations: Time
(Added and Modified)

- PROBE Estimating Basis Used: Analyze the available
historical data and select the appropriate PROBE
estimating basis (A, B, C, or D).
- Estimated Total Development Time: Using the time
regression parameters and estimated proxy size (E),
calculate the estimated development time as Time

=

β 0 Time β 1 Time * E.