Test plans, also called test protocol, are formal documents that typically outline requirements, activities, resources, documentation and schedules to be completed. Some form of test plan should be developed prior to any test.
The key reasons for developing test plans are:
Titles and order of sections within a test plan vary significantly from company to company, given differences in test types, strategy, scope and industry. Examples of tests which should have plans or protocol written for them include medical, non-medical, field, lab or production studies, design of experiments (DOE), problem solving, reliability or software regression tests, and design assurance, evaluation or validation tests.
Beginning of the Plan (typically background-related information) – Suggested considerations for information to be included in the beginning of the plan are header information, title, date, author, file code, project number, product/device/model description, sub-components of that product actually being tested, to whom the report is written, test number and revision, and references to other related documents. References might include industry standards, brainstorm documents (fishbone diagrams, FMEA/FTA/FMECA studies, related V&V protocols and reports, field history or rejection reports, company procedures, related website links, etc.). Cover pages and a table of contents should be considered for large plans. Most plans contain an explanation of what the test is about (i.e. summary, introduction, abstract, background, purpose, history, etc.). Some plans also include test type and strategy information, definitions, important terms or key words, approval signatures, return on investment and/or other justification information.
A free Word template for a test plan with common sections already setup accompanies this article. Using details from previous test plans, statistical software, company or project logos, and other materials, you can cut and paste in the template and shorten your test plan development time. Or save yourself and your company even more time, money, risk and related trouble by using the template to assist you in developing your own test plan format. Of course, you will want to remove sections that do not fit the way you do business.
Middle of the Plan (typically scope-related information) – Suggested considerations for information to be included in the middle of the plan are a data collection or sampling plan (including sample size, confidence acceptance levels and sampling techniques), test conditions or setup instructions, a test procedure specifying exact measurements to be taken, test monitoring requirements, and resources (equipment and personnel) to be used including responsibilities. Most plans contain some form of flow chart, process or value stream maps, assumptions that need to be made and why (including statistical distribution related as applicable), a work breakdown structure or schedule, and/or how the test factors (response Ys and control Xs) were selected. Some plans include special customer or site-related requests or considerations, measurement system capability information, and how test-related problems are to be reported and corrected (i.e. failure reporting and corrective action system). Also include unresolved issue reporting.
End of the Plan (typically analysis-related information) – Suggested considerations for information to be included in the end of the plan are statistical techniques to be used, the hypothesis to be tested, the power of the test matrix and/or why it was chosen (for DOE) and a definition for test success (pass/fail criteria as possible). Most plans include how the data is to be analyzed, contingencies for how to handle different types of preliminary or insufficient results, how the conclusions are to be reported or summarized (i.e. significance with confidence, pass/fail, etc.). Some plans also include references and/or a bibliography, appendices that might be needed, and copyright or proprietary information messages as applicable.
It is easy to see how test plans are an important and sensible part of performing an experiment. They save time and money, assist in getting the best results and can facilitate speedy test report writing.