Lecture
In general terms, planning an experiment is the organization of its conduct in accordance with the assumed experimental model, through a mental comparison with a flawless model of its realization, in order to obtain reliable data.
Planning presupposes that in the experimental hypothesis the IV and DV are made concrete and, at the methodological level, operationalized.
Three traditions in the understanding of planning:
1. The choice of a scheme (plan) for obtaining data to test a causal hypothesis. The researcher chooses one or another of the available set of schemes, comparing their possibilities from the standpoint of bringing the experiment closer to the flawless one.
The experimental plan (design) includes the specification of the scheme for presenting the IV conditions to different groups of participants or the sequence of IV levels presented to a single participant, as well as the number of trials or participants (n). It is also the plan for recording the DV.
Here certain substantive aspects of planning are omitted, for example, the problem of correlating hypotheses of different levels.
2. Determining the type of variables from the standpoint of the specified hypothetical constructs and the question of the operationalization of variables, along with the choice of methodological means, which reflects the interrelation of the substantive and formal aspects of planning.
3. Planning with a view to the subsequent use of statistical decisions about experimental effects, the specification of the minimal effect.
Points 1 and 3 constitute formal planning, the basis for the inference about the experimental fact. Here internal and operational validity are evaluated.
Formal planning is possible in those studies in which the principle traditional for the natural sciences is used: the variables (the IV and additional variables) are represented and managed independently of one another.
If there is more than one managed variable, then the principle of isolated conditions is adopted. The principle of isolated conditions: the levels of each variable may be combined with the levels of the other variables, and from the relationships of the individual variables one can construct their overall effect – the result of the action of the IV and the interaction effects.
Formal planning is aimed at the choice of a scheme, a plan for organizing the interactions, and the specification of the minimal effect (in the differences in the DV).
Substantive planning (point 2) – at the stage of formulating the hypotheses, the specificity of the psychological reality under study must be preserved, made concrete in the basic processes singled out for investigation.
Here the type of variables is determined from the standpoint of the specified hypothetical constructs and the resolution of questions about the operationalization of the variables, along with the choice of methodological means.
Substantive planning is also connected with the transition from formulating the theoretical hypothesis to the experimental one, with determining the type of experiment, and with evaluating operational, construct, and external validity.
Substantive planning precedes formal planning.
It is interrelated with formal planning, and therefore cannot always be singled out as a separate stage. The stages of substantive planning:
1. formulating the EH; in the case of theoretical hypotheses, evaluating construct validity;
2. controlling the type of variables, as well as deciding on the type of experiment: laboratory, artificial, field.
3. substantiating all the interpretive components within which an understanding of the established relationship is achieved, which is connected with the introduction of the notion of hypothetical constructs.
4. control over the inference as the organization of reliable generalizations.
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