Ordinal Data vs Interval Data
Ordinal and Interval are types of data. These are actually different ways of representing and classifying information. Both types of data are important as they provide user information to measure different aspects using statistics. If you are into research, you require both types of data frequently which means you need to understand the differences between the two data types.
Ordinal data refers to an arrangement of data on a scale. For example, there can be a variable X that pertains to the number of days subjects have been fed a special diet, and variable Y could measure the ranking of these individuals in a race. In such a data, it is possible to correlate the effect of variable X on variable Y.
There is a meaningful continuous scale of measurement and the data is also at an interval level. Here equal differences between values in scale correspond to real differences between physical quantities which the scale intends to measure. An example would be a collection of measurement of heights of different individuals. It can be safely said that the difference in height of a person who measures 1.8 meter and the one who is 1.7 meter tall is the same as the difference between a person who is 1.9 meter and another who is 1.8 meter tall.
The data that has been arranged in intervals can be arranged on the basis of ranks. This implies that interval data can be converted into ordinal data. However, the same cannot be said about ordinal data as it cannot be converted into interval data. However, interval level data reveals more than ordinal level data.
Ordinal data is based upon rankings. For example in a race of 100 meters, one who wins the race may take 11 seconds, 2nd place holder 11.5 seconds and third rank holder 12.5 seconds. Since the time interval between different ranks is not fixed, all you know is the ranks of different individuals. Interval data, as the name implies is based upon a scale that is continuous. On a temperature scale, you have values such as 50 degrees and 51 degrees. You know that the difference is of 1 degree.
Difference between Ordinal Data and Interval Data
As such it is clear that the biggest difference between ordinal and interval data is that the scale is not uniform in ordinal data, while it is uniform in interval scale. Another difference of course is the fact that interval data reveal ore information than ordinal data.