Charts- what type to pick? Numbers don't lie, but a bad chart decision makes it extremely difficult to understand what those numbers mean. Before you put together another Lab report or presentation, make sure you pick the right type of chart to clearly communicate the information you want to share. Here's how.

First Understand the Message You're Trying to Present with Your Data – What question are you asking in your investigation? – How have you been asked to show your understanding of scientific knowledge using your collected data?

When you're putting together a chart, you're trying to show one of four things with the data you have: – a relationship between data points, showing how one set of data point changes (the dependent variable) in relation to a second set of data points (the independent variable). – A comparison tries to set one set of variables apart from another, and display how those two variables interact, like the number of visitors to five competing web sites in a single month. – A composition tries to collect different types of information that make up a whole and display them together, like the search terms that visitors use to land on a website. – A distribution tries to lay out a collection of related or unrelated information simple to see how it correlates, if at all, and to understand if there's any interaction between the variables, like the number of bugs reported during each month in a year.

Next, Select the Best Arrangement Once you understand what message you're trying to send with the data you have, it's time to select the best method for displaying that information. Different chart types cater best to different methods.

Example of Line Graph used to show relationship of data Line charts (essentially, scatterplots with a defined trend) are better suited for relationships.

Example of Bar Chart used to show comparison of data A Bar chart tries to set one set of variables apart from another, and display how those two variables interact, for example how High three different plants grow in 4 different locations over the space of a month

Examples of Scatter plot best used to show distribution of data

Example of Pie Chart Pie charts do well when you're trying to communicate a composition, but make for poor comparisons or distributions (although Tufte would argue that there's no good use for a pie chart.)