Why are Line Plots SO hard?!





I don’t know about your class, but my students have always had a harder time understanding line plots than they did with pictographs and bar graphs.  Line plots just didn’t seem to make sense to my kids, so I started thinking about why that is and how to teach line plots in a way that does make sense.

One of the main causes of confusion with teaching line plots is that the categories are numerical, as well as the scale, so kids have to navigate two separate sets of numbers.  In a pictograph or bar graph, there are usually categories such as “colors” or “sports” or “foods” that are not numerical values.  But in teaching line plots, the categories are numbers- like “number of siblings” or “1 ¼ inches.”   Kids naturally mix up these numerical categories with the number of data points IN that category, and confusion ensues.

Here are some ways teach line plots so we can support students and help them keep the categories and data points straight:

*Start by teaching line plots using non-numeric categories.  Have the students make line plots of their favorite color or sport or food.  This will help them gain familiarity with how line plots work without potential for confusing the two sets of numbers. 



*Teach line plots by using other concrete objects, such as counters or blocks or the actual objects you’re measuring.  The Xs on a line plot are really abstract for kids to deal with.  Using concrete objects will help them connect the data they are collecting with the representation on the graph.

*Use sticky notes with Xs on them to mark the data points.  The advantage to using sticky notes is that you can write on the back of them as well, to track the data.  Students can write their names on the back, then add their X to a class line plot.  If and when confusion arises, they can go back to the actual data by looking to see whose sticky note (and data point) it is.

* Ask and answer a LOT of questions.  When students are asking and answering questions about the line plot- even simple ones such as “How many people have 2 siblings?- it forces them to really think about the data in concrete terms.  The more they can ask and answer questions from looking at the line plot, the more they can continue to check their ideas against the actual data, and the less likely they are to get confused.

*Practice!!  Make line plots all year long so that students become really familiar with them.  Plot the number of pages/ minutes/ books read, the rain/ snowfall, the time it takes to get from one place to another, transition times, etc.  The more variety and the more ways kids get to connect actual data with the representations on the line plot, the more solid their understanding will be.

*Use line plots to reinforce other math concepts.  Line plots are especially great for working with repeated addition or multiplication.  If 4 students say they have 3 siblings, how many siblings is that all together?  Each X is one student with 3 siblings.

*Always go back to the data when teaching line plots.  When confusion arises, as it inevitable does with line plots, remind the students to go back to the data.  How many students said they have 3 siblings?  Who are they?  Name those students so we can count them!

Pssssssst…

If you’re looking for a complete, ready-made unit that follows these strategies and is designed to help students build and apply their understanding of line plots, check out my second grade or third grade Common Core-aligned line plot units. 



Happy (line plot) Teaching!!

Christine Cadalzo