The best practice in product validation is that the evaluation criteria should be the same as what was used to measure the requirement. Product validation is a process that confirms that the product meets the stakeholder needs and expectations and delivers value to them. Product validation involves testing and verifying the product against predefined criteria and standards that reflect the requirements. The evaluation criteria should be consistent with what was used to measure the requirement during analysis, as this ensures that there is no discrepancy or deviation between what was specified and what was delivered. The measurement of the requirement should not be based on the average of two or more evaluations, as this is not a best practice in product validation. Averaging two or more evaluations may result in inaccurate or misleading results, as it may mask or dilute any errors, defects, or variations in the product quality or performance. Averaging two or more evaluations may also introduce bias or subjectivity into the validation process, as different evaluators may have different methods, tools, or perspectives for measuring the product. There should not be two separate measurements for evaluating each functional requirement, as this is not a best practice in product validation. Having two separate measurements may create confusion or inconsistency in the validation process, as it may lead to conflicting or contradictory results, depending on how each measurement is defined, performed, or interpreted. Having two separate measurements may also increase complexity or redundancy in the validation process, as it may require more time, effort, or resources to conduct and compare each measurement. Two or more testers should not test the product using the same test cases so that their evaluations are consistent, as this is not a best practice in product validation. Having two or more testers use the same test cases may result in duplication or inefficiency in the validation process, as it may waste time, effort, or resources to perform identical tests without adding any value or information. Having two or more testers use the same test cases may also reduce effectiveness or reliability in the validation process, as it may overlook or ignore any errors, defects, or variations that are not covered by those test cases. References: Business Analysis for Practitioners: A Practice Guide 1, page 113-114; PMI Professional in Business Analysis (PMI-PBA)® Examination Content Outline 2, page 17-18.