Final answer:
Researchers must be concerned with the validity of the scores from a sample to ensure the results of the study are applicable and meaningful. Lurking variables and participant expectancy can be controlled by randomly assigning subjects to treatment groups, utilizing single-blind study designs, and including a placebo when appropriate.
Step-by-step explanation:
Researchers and consumers of research must be concerned whether the scores obtained for a sample of subjects are valid. Validity refers to the extent to which a concept, conclusion or measurement is well-founded and corresponds accurately to the real world. This is a crucial component to consider in any research, as it dictates if the results are applicable and meaningful in terms of the topic of study. In experimental design, controlling for lurking variables and having a random assignment to different treatment groups eliminates biases and ensures that the only differences observed between the groups are due to the imposed explanatory variable.
In the context of testing, it is also important that the test scorers are unaware of the participants' grouping to avoid experimenter bias, which could occur if the researchers' expectations influence their interpretation of the data. This is typically addressed through a single-blind study design. Additionally, employing a placebo can control for participant expectations potentially impacting the experiment's outcome.