The conceptual basis of the experimental research.

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The structure of the experiment should take into account that the units of the sample, as well as the units of the target population, are complex systems of numerous characteristics that interact dynamically in space and time. This complexity requires a complete and sufficiently detailed description of these characteristics according to their role in the causal relationship that is the object of the inferences, and the identification of the important ones involved in this relationship, and, particularly, the confounding of effects of experimental factors with effects of extraneous characteristics. Precise and unbiased inferences about causal relationships of characteristics can be achieved based on a conceptual framework that adequately considers this complexity and experimental control that reduces and makes unbiased this confounding and, consequently, guarantees the desirable precision and unbiasedness of these inferences.

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