What chart type is best to compare data side by side?

A bar chart is particularly effective for comparing data side by side because it displays categorical data with rectangular bars, where the lengths of the bars represent the value of the data they correspond to. This visual representation allows for an easy comparison of quantities across different categories. Bar charts can clearly illustrate differences in value, making them suitable for situations where one needs to analyze data sets that are to be compared directly.

In cases where one might consider the other options: line charts excel at showing trends over time but are less effective for direct comparisons between distinct categories. Pie charts are great for showing proportions of a whole but do not facilitate easy side-by-side comparisons of values. Scatter plots visualize relationships between two continuous variables, which is useful for correlation analysis but not for straightforward category comparisons. Thus, the bar chart stands out as the optimal choice for side-by-side data comparison.