1. Effects of Reuse on Quality, Productivity and Economics
Wayne C. Lim, 1994

2. Two Case Studies Manufacturing Productivity (MP) section of HP
Produces software for resource planning
Reuse: Started in 1983
Reuse of code, applications, architecture utilities
Code in Pascal and SPL
San Diego Technical Graphics Division
Produces firmware for plotters and printers
Reuse: Started in 1987
Reuse of code in C

3. Result: Reuse Assessment
An analytical and diagnostic method to evaluate qualitative and quantitative aspects of reuse is developed.
Data on improved quality, productivity and economics is analyzed.

4. 1. Quality Improvement
Reuse gave 2-4 times reduction in number of defects. Reasons are:
Defects found in each reuse are accumulated.
Reuse gives incentives to prevent defects earlier.
Cost of prevention may be averaged over a greater number of products.

5. 2. Productivity
Reuse encourages specialization in areas as use interfaces, etc.
Fewer products are created from scratch.
Reuse can improve maintainability and reduce maintenance costs.
MP experienced 57% increase, STG about 40%.

6. 3. Time to Market
If reuse used on the critical path of development, time to market is reduced.
STG experienced 42% reduction.

7. Reuse costs (1) Includes creating or purchasing Reuse work products
Libraries
Tools
Reuse process
Integration costs

8. Reuse costs (2)
Findings show that relative cost of producing a reusable work product is percent higher due to:
time to required to understand the multiple contexts in which the product is used.
More complex design
Integration cost of about 20%.

9. Net-present-value method
Take the estimated value of reuse benefits and subtract the associated costs, taking into account the time value of the money.
MP found that the break-even (recover costs) point occurs in the second year. Return on investment was 422% over 8 years.
STG found the break-even point in the sixth year, return on investment 216%.