Mode

The mode is a type of descriptive statistic that researchers commonly use to characterize the data from their studies. Along with the mean (average) and median, the mode constitutes one of the measures of central tendency—a general term for a set of values or measurements located at or near the middle of the data set. The mode is calculated as the most frequently occurring value within a set of observations.

For example, in a data set containing the values 1, 1, 2, 3, 4, 5, 6, 7, 8, and 9, the mode would be the value 1, as it is the value within the data set that appears most often. However, a data set can have more than one mode, in which case, it is bimodal or even multi-modal. For instance, in a data set containing the values 1, 1, 2, 2, 3, 4, 5, 6, 7, 8, and 9, the modes would be 1 and 2, as they appear the most often.

The mode is commonly used to measure the most popular value among a set of categorical values. For instance, in a response to a survey question that has four choices: A (selected 15% of the time), B (50%), C (15%), or D (20%), the mode would represent the most popular choice among the four choices A through D. In this example, the mode would be B, with 50% of the selected values. The mode can also be used with other data scales (ordinal, interval, ratio), but researchers should be careful to select the appropriate metric to best represent the data available. Depending on whether the data are distributed uniformly in a normal distribution (bell-shaped curve) or skewed in one direction or another, the mode may or may not be equivalent (or even close in value) to the mean or median.