IB Digital Society 3.1E Representing Data Notes

3.1E Representing Data

From Raw Data to Representation

1. Raw figures are hard to read in bulk. Representing data turns them into a visual form the eye can take in quickly.
2. Data visualization maps numbers onto things the eye reads quickly, such as the height of a bar or the slope of a line. A trend hidden in a column of figures becomes visible as a rising line.
3. Every representation is a choice. What you show and what you leave out decides which parts of the data the reader notices.

Choosing the Right Chart

1. Start from the question you want to answer, then pick the chart that fits it. The wrong shape can bury your point.
2. Bar chart: compare separate categories by reading heights against each other.
3. Line chart: show change over time as a slope you can follow.
4. Pie chart: show how one whole divides into parts, but it works badly past a few slices.
5. Scatter plot: show a relationship between two variables; a cloud drifting upward hints the two rise together.

Infographics and Spatial Representations

1. An infographic weaves numbers, images, and short text into one designed picture that tells a story, aimed at a general audience.
2. Its strength is reach: shareable and engaging, it can carry a message to people who would never open the underlying report.
3. That reach is also the risk. Because an infographic is designed to persuade at a glance, style can crowd out substance and turn a messy finding into a confident headline the data does not support.
4. Location data is shown on a map; a choropleth shades each region by value, making the concept of space legible.
5. Connection data calls for a network diagram, drawing each thing as a node and each relationship as a line, revealing hubs and clusters a table could not.

When Visualizations Mislead

1. Because a representation is a choice, the same honest numbers can be framed to tell very different stories. That makes it an ethical matter, not only a technical one.
2. The classic trick is the truncated axis: a bar chart starting at ninety-five not zero can make a rise from ninety-eight to one hundred look enormous.
3. Cropping the range or choosing a flattering time window bends the reader's impression without faking a single data point, so the reader draws a stronger conclusion than the figures justify.

Representation as Power and Access

1. Whoever makes the representation decides what story the data appears to tell, which is a real form of power. Even with true numbers, the framing carries the maker's choices.
2. Representation also decides who can understand the data. A red-green chart excludes many colour-blind readers; an image with no text alternative shuts out screen-reader users.
   1. Accessibility choices decide which people and communities are actually included in the audience.
3. Reading a representation well means asking not just is this chart clear, but whose story does it tell, who can read it, and what has been left out.