Corroborating Information: Evaluating and Drawing Conclusions About Data
Overview:
You will learn:
- To understand how charts, graphs and maps present data
- How to connect the data presented in charts, graphs and maps to bigger trends in history
- How to use that data and your evaluation of its significance to draw your own conclusions
What Is Data?
Listen to the sound clip below:
- Data = evidence
- Qualitative data = evidence expressed in language
- Quantitative data = evidence expressed in numbers
Sources of Data
Data comes from a number of different places including experiments, statistics, and opinion polls. Explaining the source of the data and what it represents is important.
Data interpretation must stay close to the source. In other words, if the data collected is about voting patterns of women, do not discuss voter registration by women – these are two different topics.
Understanding the source, and knowing its limitations, is a big part of using data effectively.
Data Needs Context
Data by itself won’t make much sense. It would be like shouting “1968!” in the middle of the school cafeteria: no one would understand the meaning or purpose without further explanation.
Data requires some explanation, even if it is just a label or a title. An explanation of the data, for example what it represents and why it’s important, is a big part of historical writing.
For example, shouting “1968” followed by an explanation that it was a critical year in the Civil Rights Movement, makes much more sense!
Types of Data Presentation
Today many people talk about “data visualization.” It’s a new interest in an old practice – determining how to display a lot of information in a way that people can understand.
Generally, data is displayed in historical texts in one of three ways:
- Maps
- Charts
- Graphs
Maps, charts, and graphs each represent data in different ways.
Maps
Maps are graphic visualizations that represent the movements or interactions of people, animals, or things in a specific physical space. Maps also have a time component, as well.
Look for the following elements when reading a map:
- Title: subject of the map
- Key or legend: explains symbols used on the map
- Scale: explains how distance is represented
- Content: what the map is about…what information does it present?
Maps – Example
Click here to view an interactive activity that describes the parts of a map and tests your understanding!
Charts
Charts are graphic displays of the relationship between two or more variables. They can display either quantitative or qualitative information. Charts appear in many forms including tables, diagrams, bar charts, pie charts, and more. Charts also are known as “diagrams.”
Look for the following elements when reading a chart:
- Title
- Key
- Labels
- Content
You’ve read charts in math class, so they should be familiar to you!
Charts – Example
Historical texts often present information in a table, a common type of chart.
Look at the table that includes information about poverty rates in the United States from 1959 to 1981. The numbers represent the percentage of the population in poverty, categorized by physical location and race. This table also shows a pattern of change over time.
Reading a chart with numbers can be much easier than reading a lengthy description about the information in the chart.
Graphs
Graphs are specialized charts. Graphs represent the relationship between two or more variables; time is often one of the variables. As a result, graphs indicate trends, or patterns of change over time.
One of the most common types of graphs is the line graph that connects individual data points. As you read, check to see what information is being conveyed to you across the x-axis and the y-axis.
Look for the same elements on a graph as you would on a chart:
- Title
- Key
- Labels
- Content
Graphs – Example
The graph below from Wikimedia Commons displays poverty rates from 1959 to 2013.
While the two graphs depict similar information — U.S. poverty rates over time — the top graph displays the number of people in poverty while the bottom graph shows the percentage of the population in poverty.
In both cases, the y-axis displays the population in poverty while the x-axis shows the year. This graph displays the historical trend over time.
Evaluating Data
Listen to the sound clip below:
Examine data to determine if the source is credible:
- Who collected it and why
- When and how the data was collected
- What was collected
- Its relationship to other data
Civil Rights Movement
The Civil Rights Movement started with a few protests in the South, but grew over time. Eventually, the Civil Rights Movement expanded to include many issues, many protesters, and many locations. No longer limited to the South, by the late 1960s, protests sprung up around the United States in the Northeast, Midwest, and the West.
Example – Civil Rights Movement Map
Look at the interactive map Civil Rights Hot Spots from PBS to see the locations of significant events during the Civil Rights Movement. Click on the points on the map to read a description of protests that
occurred at that location. As you look at the map consider the questions:
- What information does the data include?
- Who collected the data and why?
- When and how was the data collected?
- How does this data relate to other sources or information?
Listen to the sound clip below for an analysis of the map and its data.
Example – Civil Rights Movement Bar Chart
The bar chart below shows the spread of the sit-ins in the year 1960. As you analyze the bar chart, consider:
- What information does the data include?
- Who collected the data and why?
- When and how was the data collected?
- How does this data relate to other sources or information?
Source:“Freedom Now” in Digital History
Listen to the sound clip below for an analysis of the bar chart:
Example – Civil Rights Movement Line Graph
Look at the line graph When did the 1960s Black-led Nonviolent Protest Activity Peak? (located on page 7) from Princeton professor, Omar Wasow. As you read the line graph, consider the following:
- What information does the data include?
- Who collected the data and why?
- When and how was the data collected?
- How does this data relate to other sources or information?
Listen to the sound clip below for an analysis of the line graph:
Putting the Data Together
Listen to the sound clip below:
To evaluate data, it is helpful to compare different sources. You can integrate, or put together, data from multiple sources to form new understandings of a topic.
Evaluating the Spread of the Civil Rights Movement
Looking at the data, you see a distinct trend emerge: participation in the Civil Rights Movement spread from a limited number of locations in the South to many places around the country.
Taken together, each presentation of data shows an increase in the number of protests and the number of participants in these protests over time.
Each set of data tells a story!
Conclusion
You learned how:
- Charts, graphs, and maps present data
- To connect the data presented in charts, graphs, and maps to bigger trends in history
- To use that data to draw your own conclusions