About this lesson
Trial and Error
Trial and Error is an experimental methodology where subject matter experts hypothesize the critical independent factors that will create a desired (or specifically undesired) response from the dependent factors. The experiments are done with these factors. If the experiments are not successful, another set of factors is selected.
When to use
Trial and error experimental approach is appropriate when there is a specific goal or response that is desired from the dependent factors and there are subject matter experts who can confidently select the appropriate independent factors for that experiment.
When using the trial and error method, it is vital that the two conditions mentioned above are met. First, the goal of the experiment will have a clear pass or fail criteria. That is so that the experiment can be determined as a success or failure. The second is that the subject matter experts must have adequate knowledge and experience to select the correct independent factors to be examined during the experiment. If either of those conditions is not true, then this method will likely create delays and overruns to the project.
If these independent factors selected do not create the desired response from the dependent factors, then a new set of independent factors must be selected. This pattern is repeated until the desired response is achieved. When there is an ambiguous goal, or the factors are just wild guesses, this approach often requires many iterations, leading to the delays and overruns.
When the aforementioned conditions are met, this approach will be the fastest and lowest cost experimental design approach. By leveraging the expertise of the subject matter experts and focusing the experiments on a specific goal, the number of tests can be held to a minimum.
One caution with this approach is that the “solution” may not truly solve the problem. If other factors are also significant, but not controlled in the experiment, the dependent factor results may be acceptable due to the uncontrolled factor rather than the independent factors that were tested.
Hints & tips
- The efficacy of this approach is highly dependent upon the knowledge and experience of the subject matter experts. Work the best you can find, either internal or external and from any department in the business.
- This is a difficult methodology to estimate. An optimistic estimate is that the first set of factors are the correct factors and no further experiments are needed. Most of the time that will be true, but when it isn’t, additional unplanned tests are needed and then this approach can quickly create massive delays and overruns.
- If the goal is to gain knowledge about a technology or product, use a different approach. This approach is best suited for testing a particular condition or to achieve a particular performance level.
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