Question

Discuss why correlation is necessary but not sufficient to establish causation and give an example

Answer 1

Correlation define the relationship between two variables in which the change in value of one variable is associated with change in the value of another variable. For example, achievement level increases with the increase of intelligence level.

There are three types of correlation,they are-

1) Positive correlation: when the value of one variable increases with increasing the value of another variable. For example, achievement level increases with the increase of intelligence level.

2) Negative correlation: when the value of one variable decreases with increasing the value of another variable. For example, weight is decreasing with increasing the height of the body.

3) Zero correlation: changing in the value of one variable does not affect the value of another variable. It refers that there is no relationship between two variables.for example, there is no relationship between the amount of water drunk and level of intelligence.

Why correlation is necessary-

1) Correlation helps us in determining the degree of relationship between variables. It enables us to make our decision for the future course of actions.

2)  Correlation analysis helps us in understanding the nature and degree of relationship which can be used for future planning and forecasting.

3)  Forecasting without any prior correlation analysis may prove to be defective, less reliable and more uncertain. If it is based upon the result of correlation analysis, it will be more reliable.

4) it helps us to know whether the null hypothesis is valid or not. Generally zero correlation refers that null hypothesis is valid.

- Correlation is important in the field of Psychology and Education as a measure of relationship between test scores and other measures of performance. With the help of correlation, it is possible to have a correct idea of the working capacity of a person. With the help of it, it is also possible to have a knowledge of the various qualities of an individual.

After finding the correlation between the two qualities or different qualities of an individual, it is also possible to provide his vocational guidance. In order to provide educational guidance to a student in selection of his subjects of study, correlation is also helpful and necessary.

Correlation is not sufficient to establish causation-

Correlation is not causation means that two variables or things correlate it does not mean that one variable is the cause of another. Only on the basis of level of relationship or type of relationship (whether it positive, negative or zero) we can not say that one is the cause of another variable. For example,  just because people in the UK tend to spend more in the shops when it's cold and less when it's hot doesn't mean cold weather causes frenzied high-street spending.