Creating Stem-and-Leaf Plots in SPSS- A Tutorial

What Is a Stem-and-Leaf Plot?

A stem-and-leaf plot is a way to display numerical data while keeping the actual values visible. Unlike a histogram that only shows distribution shape, a stem-and-leaf plot shows every single data point.

The "stem" is the leading digit(s) and the "leaf" is the trailing digit. It's basically a sideways histogram that still lets you see the raw numbers.

Why Use Stem-and-Leaf Plots in SPSS?

SPSS gives you several graphing options, but stem-and-leaf plots have their place:

• Quick visual inspection of your data distribution
• Identifies outliers by eye
• Shows data granularity that histograms hide
• Useful for small to medium datasets (works best with fewer than 200 values)

For large datasets, histograms and box plots do a better job. Stem-and-leaf plots shine when you need to verify exact values or spot unusual patterns.

Creating a Stem-and-Leaf Plot in SPSS

Here's the straightforward process:

Method 1: Using the Legacy Dialogs

This works in all SPSS versions:

1. Click Analyze in the menu bar
2. Go to Descriptive Statistics
3. Click Explore
4. Move your variable into the Dependent List box
5. Click Plots button
6. Under "Descriptive" section, check Stem-and-leaf
7. Click Continue, then OK

Method 2: Using Chart Builder (Newer Versions)

For SPSS 20 and later:

1. Click Graphs → Chart Builder
2. Select Stem-and-leaf plot from the gallery (or find it under "Histogram")
3. Drag your variable to the x-axis
4. Click OK

⚠️ Note: The Chart Builder method may not always produce the classic stem-and-leaf display. The Explore procedure is more reliable for this specific chart type.

Understanding the Output

When SPSS generates a stem-and-leaf plot, here's what you're looking at:

Stem width: 10
Each leaf: 1 case(s)

Stem & Leaf
2     3 5 8
3     1 2 2 4 6 7 9
4     0 0 1 3 5 8 9
5     2 4 6

In this example:

• The stem represents tens (2 = 20, 3 = 30, etc.)
• The leaves represent ones (3, 5, 8 = 23, 25, 28)
• "Stem width: 10" means each stem increment equals 10 units
• "Each leaf: 1 case" means each digit represents one observation

Customizing Stem-and-Leaf Plots

SPSS doesn't give you much control over stem-and-leaf plots compared to other charts. But you can adjust the output in the Explore dialog:

• Stem-and-leaf — toggles the plot on/off
• Histogram — overlays a histogram for comparison
• Normality plots — adds normality tests and P-P plots

That's basically it. SPSS treats stem-and-leaf as a byproduct of exploratory analysis, not a standalone visualization tool.

Stem-and-Leaf vs. Other Charts

Common Issues and Fixes

The plot shows decimals instead of whole numbers

Your data might be stored as scale with decimal places. Use Compute Variable to round: ROUND(yourvar, 1) or multiply then round, then divide back.

Too many decimal places in leaves

Stem-and-leaf plots work best with whole numbers or one decimal place. Recode your variable to reduce precision if needed.

Output doesn't appear

Make sure you selected Plots in the Explore dialog and checked the stem-and-leaf option. The default might only show descriptive statistics.

When to Use Stem-and-Leaf Plots (And When Not To)

Use them when:

• You need to verify exact data values
• Dataset is small (under 200 cases)
• You're checking for data entry errors
• Teaching basic statistics concepts

Skip them when:

• Dataset exceeds 200 cases — output becomes unreadable
• You need publication-quality graphics — use histograms instead
• Comparing multiple groups — box plots work better
• Presenting to non-statistical audiences — stem-and-leaf confuses people

Exporting Your Stem-and-Leaf Plot

SPSS doesn't let you export stem-and-leaf plots as image files directly. If you need one for a report:

1. Copy the output by right-clicking the plot → Copy
2. Paste into Word, PowerPoint, or image editor
3. Or screenshot the output window

It's not elegant, but that's your only option in SPSS.

Bottom Line

Stem-and-leaf plots in SPSS are functional but basic. They're tucked away in the Explore procedure and offer almost no customization. Use them for quick data checks, not for final presentations.

If you need a visual representation that shows distribution shape, just use a histogram. If you need to see actual values, export your data to Excel and sort it there.

The stem-and-leaf plot exists in SPSS because it's a traditional statistics tool, not because anyone requested good customization options for it.