Historians often write about people and very frequently about large groups of people. It can help to understand the relative numbers of individuals involved in a project by creating a visual representation of your data. The samples here emphasize different forms of visualizations and their respective readings.
Visualization: Histogram, Line graph, Pie chart
With Tableau, you can create basic visualizations like chart, graph, histogram, and combine them together in a dashboard view, with Tableau dashboard, you can compare a variety of data simultaneously.
Skill level: Basic to intermediate
Tool(s): Tableau Desktop, Tableau Public
Line graphs are charts used to visualize the value of something over time. Scholars can use these graphs to demonstrate demographic shifts, such as an increase in an ethnic group over time. Or, scholars can add layers of complexity by using by comparing datasets.
Here, viewers can see the clear, exponential increase in numbers of "missing" people (red) over a ten year period against the U.S. Federal immigration statistics for Irish citizens during the same period (blue).
Skill level: Basic
Tool(s): Tableau Desktop, Tableau Public
In order to draw further to draw further analysis from a dataset, it needs to be put into context with additional information. In this case, the chart to the right puts the increase in the "Information Wanted" entries in conversation with the US official statistics on immigration from Ireland.
Note that official government statistics are notorious for their inaccuracy. The exact numbers provided should not be taken at face value but rather as expression of great increase or decrease.
Data entry took about four minutes for the two columns using Excel for the chart and U.S. Bureau of the Census, Historical Statistics of the United States, Colonial Times to 1957 (Washington, D.C.: U.S. Government Printing Office, 1965), 57.
Histograms are charts used to visualize the the frequency distribution of continuous variables.
To the right, for example, readers can clearly see the age distribution of the "missing" people in the "Information Wanted" data for 1840-1850. It becomes quickly clear that the majority of the "missing" were in their mid-teens to early 20s.
Skill level: Basic
Tool(s): Tableau Desktop, Tableau Public
Pie charts shows proportions and percentages between categories, by dividing a circle into proportional segments.
Here, users can easily differences between numbers of men versus women among those "sought" in the "Information Wanted" classifieds. There are, however, limitations. This chart does not suggest differences in U.S. immigration but only that people were looking for more men than woman.
Skill level: Basic
Tool(s): Tableau Desktop, Tableau Public
Description: Bubble chart display data as a cluster of circles, it is primary used to depict and show relationships between numeric variables. Here, viewers can get a rapid understanding of how many people in the "Information Wanted" dataset were involved in different industries after their arrival in the United States.
Skill level: Basic
Tool(s): Tableau
Treemap is used to display hierarchical data using nested rectangles, treemap works well with hierarchical or categorical data. Here, each block of the treemap shows a group of "missing people" by their originals, the size of the block represents the number of records.
Skill level: Basic Tableau skills Tool(s): Tableau
