Kathy Iberle (Hewlett-Packard) and Sue Bartlett (IIS/STEP Technology) have developed a model to determine the ratio of software testers to software developers. The following comes from the abstract of their paper “Estimating Tester to Developer Ratios (or Not)”.
Test managers often need to make an initial estimate of the number of people that will be required to test a particular product, before the information or the time to do a detailed task breakdown is available. One piece of data that is almost always available is the number of developers that are or will be working on the project in question. Common sense suggests that there is a relationship between the number of testers and the number of developers. This article presents a model that can be used in describing that relationship. It is a heuristic method for predicting a ratio of testers to developers on future projects. The method uses the model to predict differences from a baseline project. A reader with some projects behind her will be able to come up with a rule-of-thumb model to suit her most common situations, to understand when the model might not give accurate answers and what additional factors might need to be taken into consideration.
In the paper the authors present two case studies: (1) “MergoApp”, a e-commerce website where the tester-developer ratio was 1:4, and (2)“DataApp”, a database application to replace an Excel application, where the actual tester-developer ratio was 4:8. A copy of their model can be found at Kathy Iberle’s web site (http://www.kiberle.com/articles.htm). In addition, slides for the presentation can be found here: Estimate Slides.
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Posted in analyst, helpdesk, model, personel, programmer, spreadsheet, staffing, system admin, tech support, tagged spreadsheet, staffing on December 9, 2009 |
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TechRepublic has provided a spreadsheet model to help you determine the right number of people in your IT shop. In their approach, they focus on one category of staff at a time. In each category, a few key questions are used to focus the analysis:
- Is there a separation between application development and support?
- Do programmers work on multiple business applications?
- Are external clients supported, and if so, is there customized code for individual clients?
- Are major investments needed in software development of critical business applications?
- How big is the programming backlog, and what type of changes are being requested?
- Can the key business processes be accomplished better and more economically with a third-party solution?
- If you have external clients, can programmers be dedicated to and billed to specific clients?
2. Business application analysts and trainers
- Are new applications planned?
- Does the company support the installation of software for external clients?
- How knowledgeable are the departments and clients in the use of their business applications?
3. Help Desk specialists
- Are infrastructure calls separated from business application calls, or is the Help Desk support functions for both combined?
- How responsive do you need to be?
- Does the Help Desk have sound escalation procedures?
- What’s the level of client satisfaction for IT support?
- Is the response rate to solve user issues sufficient?
- Do you have a tracking system to monitor support calls, trends, and responsiveness?
- How many calls is the Help Desk handling now?
- What is the percentage of local users (as opposed to remote)?
- Does the company require 24/7 staffing of the Help Desk?
4. Network administrators
- Are major changes or enhancements planned/needed for the infrastructure?
- Is an experienced architect of the network in place?
- What has been the history of implementing infrastructure changes?
- Is there an infrastructure strategic plan?
- Is a change management process in place?
5. Desktop support specialists
- What are the company growth plans?
- Are major changes planned/needed in the desktop hardware/software?
- What is the percentage of remote users (other office buildings, cities, etc.)?
- Is the response rate to solve desktop issues sufficient?
6. Data Center operations staff
- Does the Data Center require 24/7 operation?
- What are the requirements for the Data Center?
- Is a “lights out” operation possible?
- Is the Data Center secure?
Using this model IT staff needs are based upon a number of factors, including the workload, anticipated needs, current capability of the staff, and maturity of the company. As much as possible, we try to quantify all the variables in each set of issues. Ultimately, it’s a judgment call based on the variable data, the level of support that you need to provide, and your experience in managing IT. If you can quantify the variables that affect levels of support, you’ll be much better equipped to determine your true needs.
A full description of this approach can be found at: http://articles.techrepublic.com.com/5100-10878_11-1061079.html?tag=e106
A copy of the IT Staffing Model in an Excel spreadsheet can be found here: http://downloads.techrepublic.com.com/5138-6321-730024.html
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Cem Kaner, a professor at the Florida Institute of Technology, has done research on the ratio of software testers to software developers. His presentation entitled “Managing the Proportion of Testers to Other Developers” is partially based on a meeting of the Software Test Managers Roundtable (STMR 3) in Fall 2001.
The study found that:
– There were very small ratios (1-to-7 and less) and very
large ratios (5-to-1).
– Some of each worked and some of each failed.
– Many remembered successful projects with ratios lower than 1-to-1 more favorably than successful projects with larger ratios.
Read the paper to find out why is there such a range of successful ratios, and why test managers be happy with relatively low ratios?
See: http://www.kaner.com/pdfs/pnsqc_ratios.pdf and http://www.kaner.com/
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According to Tim Bryce (Managing Director of M. Bryce & Associates),
If systems analysis is performed correctly, programmer productivity should improve as analysts should be providing good specifications for application assignments. In the absence of systems analysts, considerable time is lost by the programmer who has to second-guess what the end-user wants. Inevitably, this leads to rewriting software over and over again. Good data and processing specs, as provided by a systems analyst, will improve programmer productivity far better than any programming tool or technique. This means programmers are the beneficiaries of good systems analysis.
This brings up an interesting point, what should be the ratio of Systems Analysts to Programmers in a development organization? Frankly, I believe there should be twice as many analysts than programmers. By concentrating on the upfront work, programming is simplified.
Source: Bryce, Tim, “The Ratio of Analysts to Programmers”, Toolbox for IT, August 24, 2006.
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