Module 2: Selecting a Chart

Word cloud

Displays how frequently words appear in a given body of text, by making the size of each word proportional to its frequency

Column Chart

Comparison. Column charts are the standard for showing chronological data, such as growth over specific periods of time, and for comparing data across categories. Grouping a small number of sub-sets (max. 6) gives additional information about the distribution of data over smaller units, i.e. quarters or regional offices.

Histogram advantages

Comparisons Data over time Distribution Range

Stacked Column Chart

Composition. A column chart that places the data series values within combined columns showing how much is contributed by each series.

Stacked bar chart

Composition. This is a variation of the bar chart where each bar is broken into smaller units, i.e. quarters or regional offices, showing the development of the whole as well as that of the smaller units within the data set. Use a 100% stacked bar chart when you only want to show relative differences.

stacked column chart

Composition. This is a variation of the column chart where each column is broken into smaller units, i.e. quarters or regional offices, showing the development of the whole as well as that of the smaller units within the data set. Use a 100% stacked column chart when only relative differences matter.

Stacked Area Chart

Composition. This is a variation of the stacked column chart showing the development of the whole as well as that of the smaller units within the data set in a continuous flow. Use a 100% stacked area chart when you only want to show relative differences.

Histogram

Distribution The histogram is used for variables whose values are numerical and measured on an interval orr ratio scale. The line histogram is generally used when dealing with large data sets (greater than 100 observations). While a column histogram is better for smaller data sets. A histogram can also help detect any unusual observations (outliers) or any gaps in the data.

Limitations of a stacked bar chart

Harder to read the more segments each bar has. Comparing segments to each other is difficult, as they're not aligned on a common baseline.

Histogram Data Type

In data analysis, bar graphs are used to measure the frequency of categorical data, while histograms measure ordinal and quantitative (interval and ratio) data. Although the vertical axis of both graphs is discrete, the horizontal axis of a bar graph is categorical while that of a histogram is numerical.

Limitations of word clouds

Long words are emphasized over short wordsNot good for analytical accuracy (used for aesthetic reasons instead)

Bubble Chart

Relationship. Bubble chartThis chart type is a variation on the scatter plot, adding a third (dependent) variable which indicates volume or size.

Line Chart

Relationship. Line chartThe purpose of a line chart is to show trends, accelerations (or decelerations) and volatility. They display relationships in how data changes over a period of time. Choose a line chart also when the number of data points is very high and a column or bar chart would look too cluttered.

Bar Chart

Relationship. This chart type is typically suitable for comparing the size of data (horizontal axis) for a medium to large data set (vertical axis). Keep data in an order that makes sense. Either list by value or, if that's not the strength, choose a logic for the labels that makes sense, like listing them alphabetically. Added benefit of this chart type is that it accommodates for long data labels.

Scatter Plot

Relationship. This chart type works best to find and show the correlations between two variables. The data sets need to be in pairs with a dependent variable and an independent variable. The dependent (the one the other relies on) becomes the y axis and the independent, the x. Adding a trend line will help show the correlation and how statistically significant it is.

Two Axis Chart

Relationship. Two-axis chartThis chart type combines two chart types in a single chart: a column chart series and a line graph series. There are two Y-axes: each axis has its own unit and magnitude, and each data series conforms to one of these axis. This chart type is ideal if you have two (or more) variables that you want to show in the same period of time, like temperature and rainfall, and how they correlate over time.

Limitations of multi-line graphs

Without interaction, having more than 5 on the screen is hard to make sense of

Alluvial/Sankey diagram

a specific type of flow diagram, in which the width of the arrows is shown proportionally to the flow quantity