Published on december 3, 2019 by rebecca bevans.revised on march 31, 2022. There can only be one. Use creately’s easy online diagram editor to edit this diagram, collaborate with others and export results to multiple image formats. Experiments are used to study causal relationships.you manipulate one or more independent variables and measure their effect on one or more dependent variables. The example illustrates the information that an evaluator should include in each section of an evaluation plan, as well as provides tips and highlights key information to consider when writing an evaluation plan for a qed.