## Dependent variable

Together with the planning of the characteristics of an independent variable, the researcher must decide what, or what, his dependent variables will be in his study. In other words, what exactly should change in the behavior of the subjects under the influence of different levels of the independent variable.

If an independent variable is set by the researcher and controlled in the study, then he measures the dependent variable. The more accurately and more adequately the dependent variable is measured, the more accurate will be the answer to the question whether the change in the independent variable really leads to a change in the dependent variable or whether there is no connection between them.

When planning an experiment, it is extremely important to operationalize the dependent variable, i.e. give it an operational definition - clearly describe the set of actions and operations of subjects that will allow us to establish the very fact of manifestation and the level of expression of the dependent variable. In doing so, it is necessary to determine how to measure the dependent variable - whether it will be a self-report, whether the subject should demonstrate some skills (for example, successfully solve problems) or whether he should only evaluate some phenomenon (for example, solving problems by other people). It is important to determine in advance in which scales the reactions of the subjects will be measured. So, in our example, the success of solving problems can be measured by the number of correct solutions, or by the number of successfully solved tasks per unit of time, or by the amount of time spent solving each individual problem, or by the number of deadlocks in the solution of each problem, or by the complexity of the solution methods used. Which or what methods of measurement to choose, the researcher decides, based on general theoretical concepts about the processes of solving problems and the requirements of statistical methods of data processing.

Thus, in the experiment, one or more methods of operationalizing the dependent variable can be used. The use of several different internationalizations increases the confidence that the result obtained is not accidental, that changes in the dependent variable recorded as a result of the experiment are caused not by a possible measurement error, namely an independent variable. Different manifestations of the same independent variable are usually referred to as its conceptual replicas.

So, the planning of the stages of research related to the identification of the influence of an independent variable begins with the elaboration of the methods for the most appropriate operationalization and measurement of the dependent variable. To do this, all the knowledge that you have acquired, using the theme "Observation" (on the question of the operationalization of theoretical constructs) and the section "Measurements in Psychology."

As you already know, in order to prove that some event (independent variable) is the cause of the change of another event (dependent variable), it is necessary not only to check whether the dependent variable will change under the action of the independent variable, at the same time to eliminate the influence of all Other factors that could also change the dependent variable. Control of such factors is called control of the third variables.

Thus, when investigating the influence of hints on the solution of mathematical problems, the researcher can not get rid of the fact that the subjects are divided into young men and women, and girls are much more likely than boys to fall into a stupor from the kind of figures and signs of mathematical operations. As a consequence, they either refuse to solve problems, or write a response at random, which nullifies the impact of the hint. In this study, sex will be one of the additional (side) variables that can affect the success of the solution of the problem along with the change of the independent variable - the introduction of the hint. Therefore, the researcher must necessarily check, for whatever reason, the success of solving problems - under the influence of a hint or because of gender.

There are several ways to do this.

First , you can limit your research by typing only young men into the sample. But this restriction does not allow you to study how the tooltip for solving problems affects girls, the results can be used only for hints to young men.

Secondly, can equalize the number of boys and girls in the sample. This is also a method of control, in which only the independent variable (hint) has an effect, because the polo-role composition of the subjects in solving problems with different hints will be the same.

Finally, thirdly, you can collect the results from all the young men and girls and see if there is a difference in solving problems by young men and girls. If there is no difference, then the success of the solution can be explained by the influence of the clue. If the difference is present, then you need to continue research in order to understand what exactly affects the success of solving problems - the tip or gender of the subject, or a combination of these factors (when the clue is more effectively used only by young people or just girls).

But essentially, the side variables are such additional variables that were not controlled by the researcher. This can happen for various reasons. The researcher may not be aware of the existence of the secondary variable or its possible impact (as in our example, when the researcher did not know that the state of air in the room was not, and poisoning during the lunch break influenced the success of the problem solving by the subjects). In another case, the technical feasibility of the experiment could exclude the possibility of controlling the secondary variable. For example, if the study is conducted among the metro train drivers, among whom there can not be any women, the influence of the floor can not be controlled, and it will remain an auxiliary variable until a certain number of machinists-women appear.

In order to integrate all the necessary additional variables and to provide for the influence of the maximum number of side variables, the researcher should properly study the literature related to his field of research. In this literature, he is able to gather information about the factors that influence his dependent variable. The more detailed the literature on the issue of research, the better the data on other similar experiments are studied, the more the researcher knows about what factors he himself should control and how.

In the most general form, the sources of additional and secondary variables can be divided into three large groups:

- associated with the individual characteristics of the subjects;

- associated with the personality of the researcher;

- related to how the procedure itself is organized.

The influence of the personality characteristics of the test subjects is practically nonexistent

can not be eliminated from the research procedure. Therefore, when planning a study, its author, based on the literature data, should identify those personality characteristics that can affect its dependent variable, and, if possible, stabilize their influence.

In addition to the personality of the subjects, the results of their work in the experiment are influenced by their attitudes toward the research and the researcher. Among the most famous such facilities include fear of evaluation, fear of reporting too much personal information. Here people at the most directly refuse to participate in the experiment, and in the worst case they intentionally perform the task poorly, choose deliberately impossible tasks, violate the instruction, answer questions at random - in general, they do everything so that the researcher can not get any reliable information from the results their work. Even a complete failure is more desirable for such subjects, as they will justify themselves that the results of the research do not reflect their true characteristics and abilities, because they tried to perform the task as badly as possible. This setting distorts the results of the study, underestimating the true capabilities of the subjects.

Another pole of the subjects' installations is the desire to show oneself from the best side, the desire to help the experimenter. Many people consciously or unconsciously try in the situation of research (evaluation) to perform a task much better than they would have done in everyday life. They give socially approved answers, try to guess the researcher's hypotheses to cope in the best way, and not as they would normally do. This setting also distorts the measurement of the dependent variable, overstating the results.

The influence of the personality of the researcher on the results of the research is quite diverse, and besides it is very difficult to control. Factors that affect the characteristics of responses of subjects include the sex of the experimenter, his appearance, the features of speech and non-verbal behavior. The most studied factor that affects the results of the work of the subjects is the desire of the experimenter to confirm his hypothesis. In psychology, the Pygmalion effect is widely known. He already mentioned us in the chapter on the method of observation. In other words, it is called the Rosenthal effect. It is named after the American psychologist R. Rosenthal, who first studied this effect in detail.

The essence of the effect is that when the experimenter knows the goals and hypothesis of the research, his hypotheses are confirmed much more often than those of the experimenters who conduct research without knowing his hypotheses. To combat this effect, a double blind method is used, the idea of ​​which is that neither the experimenter nor the test subjects should know about the true goals and hypotheses of the investigation. For this purpose, one scientist is engaged in the planning of the study, and the assistant is his conductor.

Another way to reduce the effect of Rosenthal is to automate the research process by presenting materials on a computer monitor, using video presentations, etc. In this case, the attention of the subjects is directed not to the experimenter, but to the screen, and the features of the appearance and behavior of the experimenter are less affected by their behavior.

In any case, the detailed development of the research procedure, including the instructions and procedure of the experimenter's actions, up to individual gestures and intonations of the voice, contributes to reducing the experimenter's influence on the results of the work of the subjects.

As for the peculiarities of the procedure of investigation, they too often lead to regular distortions of the results. These distortions are very diverse, and in each specific study they need to be considered separately. Nevertheless, there are some stable features of the procedure for conducting the study, which occur quite regularly. First of all, here are the temporary effects and the associated effects of the sequence (we'll talk about them in more detail in the next chapter).

The more side variables can be controlled, the more the real experiment approaches the ideal, in which any third variables are missing at all. Speaking about the quality of the experiment, use the concepts of reliability and validity. Reliability and validity are two characteristics of the quality of experimental research, reflecting its compliance with an impeccable experiment. The higher the reliability and validity of the research, the more confidence is caused by its results and the more confident they can be used in psychological practice.

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