Longitudinal research method in psychologyusually contrasted with analyticalslice models. Recently, it has been considered in the context of identifying experimental delayed effects. Consider further what constitutes longitudinal research method.
Longitudinal method is in multiple fixation of parameters on onea person or a group of people. The slice model, by contrast, implies a comparison of indicators for the same time among representatives of different age categories. Classical longitudinal method in psychology means "continued study."
Longitudinal comparative method is in a special position in the structureanalytical techniques, social sciences, behavioral disciplines. This is due to a number of circumstances. First of all, the special situation is connected with the specificity of the tested developmental hypotheses. Equally important are the complexity of planning, organizing observations, processing results. Many authors gave in their works the classification of applied models of analysis. Considered longitudinal method, according to Ananyev, appliesIn particular, to organizational receptions.
Development hypotheses suggestthe dynamics of changes in time. However, this factor is not considered as a source or premise. It is regarded as an analogue of the independent variable. The theoretical substantiation of the possibility of temporal dynamics of changes in indicators is interpreted as development, it also provides for methodological principles for understanding this process, the position of a specific concept, as well as evaluating the planning of observation.
Longitudinal method allows you to directly refer to the verification of casualassumptions in terms of time sequence requirements and causes. Accordingly, it can bring to the realization of two key conditions for detecting communication. The first involves the study of the causes and consequences in time, the second - the establishment of covariance between them. Place prerequisites may take any impact under observation. However, they can not be interpreted as experimental, if the specialist does not manage them. Other requirements for conclusions about the causes can be obtained in successive cross-sectional or shear observations. For example, the condition on the presence of covariance among variables is revealed by intergroup differences or non-zero correlations between variables. The requirement for the absence of alternative justifications can be realized through the use of statistical or experimental control.
Features of development
Longitudinal method originated during the introduction of a systematic censuspopulation in Quebec in Canada in the 17th century. This analytical model was most developed after the First World War in America. Subsequently, at the end of the 20th century. longitudinal method entrenched in social disciplines and the science ofbehavior. The modern development of the model is determined by the improvement of information analysis techniques determined at the planning stage of observation. The authors of one of the articles devoted to the method indicate that for the most part of modern theories, statements that have a dynamic nature are indirectly or directly put forward. In other words, they appeal to the justification of a certain phenomenon in the context of the changes that occur to him or his connections with other phenomena. A similar conclusion can be made regarding psychological patterns that are established when testing hypotheses about the development, delayed or prolonged effects of effects.
Relationship with empirical observations
Hypothesis testing is a key task that performs longitudinal method. However, despite this, the findings on the developmentoften made in accordance with the results of empirical observations. They are carried out within the framework of a variety of psychological concepts using the shear method. It allows you to detect the relationship of several static variables, taken in a separate time interval. The use of the findings is determined by the presence of a tacit assumption about the equivalence of the samples through which the comparison is made, as well as historical periods for various categories of subjects. This often leads to ignoring an important source of confusion that needs special attention.
To indicate the community of people in the sample by yearbirth, the term cohort is used. In accordance with the demographic characteristics, this concept means a certain group of persons designated within a geographic or other population that has experienced similar events in a given time period. The age variable is the chronological number of years at the time of observation. In the analysis should also clarify the concept of "period". It denotes the time of measurement and the stage covered by the life of a cohort, including historical events common to its members. Formally, the community is defined as:
Cohort = Measurement period (calendar year) - age (number of years from birth).
The above equation illustrates lineardependence of measurement time, cohort and age. In this case, a source of systematic mixing that is important for the longitudinal method is expressed. People born in the same year live in general social conditions covering a specific historical period. From this follows this conclusion. A common cohort for people will be not only the year of birth, but also their “history” - the content of the period in which they live in a particular country, in specific geographical conditions, political, economic, cultural space. If this confusion is ignored, then the validity of the conclusions that a specialist using longitudinal method.
Linear dependence leads to the fact that duringcontrol of any two indicators is controlled by the third variable. If the method of cuts is used in the study, the sample of people also has a common "history", but it is different for participants in the longitudinal section and sections. This leads to a mixture of social circumstances and age. In this regard, when performing cut-off comparisons of parameters for people of different ages, the identified differences between more mature and younger subjects may not express the line of development of the main process, but the effects of the cohort. The use of the longitudinal method with multiple consecutive measurements can help to detect results not specified as a subject of research, but results from the impact of social circumstances as a historical stage specific to a given sample.
Attempts to overcome addiction
They are divided into 2 conceptual categories.The first is Mason's research. In it, the problem is supposed to be solved at the statistical level. For this purpose, models are formed by which collinearity is eliminated (absolute mathematical dependence) between the cohort, age and time interval. The second group contains approaches that presuppose a theoretical rationale for the process of excluding consideration of the impact of one indicator on the revealed lines of development or their rethinking. In this direction, some techniques were developed. Some consider the parameters of the cohort as the interaction of age and time effects. Others replace the sample with its characteristics, which can be accurately determined and measured. In the ideal case, period and cohort effects that have a fundamentally different explanatory status than time indicators are excluded from the analysis. They will be replaced with operationalized properties, which make it possible to dilute the parameters of age, historical period and the sample itself. This form of analysis is fundamentally impossible beyond the framework of a “true” longitudinal study, where many measurements are carried out on several cohorts simultaneously.
The longitudinal method allows one to test "strong" casual hypotheses when performing a quantitative assessment of the dynamic properties of development. The key objectives of the study are:
- Improving the accuracy of measurement effect.It is achieved by controlling intraindividual variability. In this case, recurring observation schemes are used, to which, among others, the longitudinal method applies.
- Testing hypotheses related to the orientation of casual connections, evaluation of their strength.
- Determination of the functional form of developmental curves or intraindividual trajectories.
- Analysis of interindividual differences. It is carried out using casual models.
In the literature, the key difference in the understanding of the considered method is the lack of consensus on the minimum number of time slices.