Measurement Bias occurs when the act of sampling causes the measurement to be impacted. In e-discovery, measurement bias could occur if the content of the sample is known before the sampling is done. For example, if one were to sample for responsive documents and during the sampling stage, content is reviewed, there is potential for higher-level litigation strategy to impact the responsive documents. If a project manager has communicated the cost of reviewing responsive documents, and it is understood that responsive documents should somehow be as small as possible, that could impact your sample selection. To overcome this, the person implementing the sample selection should not be provided access to the content.