For instance, if reducing fat intake leads to a reduction in cholesterol level, it can be said there is a causality between fat intake and cholesterol level. A control variable, or independent variable, is evaluated by monitoring changes in response, or dependent variables, related to the control. For example, if different fertilizer mixtures are the control variables, the response variable could be crop yield. For the program in question, the Hawthorne Effect could be tested by continuing the quality program but reducing management s visibility with the project. If the productivity gain remains, the Hawthorne Effect was not a factor.
Task analysis can locate a specific task that exceeds a human s capabilities.
This is done by analyzing the task, and estimating the human capabilities required. Work measurement methods do not typically allow you to understand why an operator is doing something, they only measure what a person is doing.