How to graph IEP goal progress: aim lines and trend lines

A graph answers the question a column of percentages can't: is this student going to meet the goal by the end of the IEP? Three lines do the work: the data itself, an aim line from baseline to target, and a trend line through the data.

A /r/ goal: baseline 30% on September 8, target 80% by June 5, mastery defined as three consecutive sessions at 80% or above. The trend line rises faster than the aim line, and the student met the criterion on April 20.

What goes on the graph

Data points: one per session, showing that session's result: percent correct, a count, or percent syllables stuttered. Plot them by date rather than by session number, so absences and school breaks show up as gaps.
Baseline: where the student started, from the present levels in the IEP or your first probes.
Target: the criterion in the goal, such as 80%.
Aim line: a straight line from the baseline on the baseline date to the target on the IEP end date. It's the path the student needs to be on to meet the goal on time.
Trend line: a line of best fit through the data. It's the path the student is actually on.
Mastery marker: the session where the goal's mastery criterion was first met, for example the third consecutive session at or above 80%.

Drawing the aim line

Take the example above: baseline 30% on September 8, target 80% by June 5. The aim line runs from 30% on September 8 to 80% on June 5. That's 50 percentage points over about 39 weeks, or roughly 1.3 points a week. Around January 21, halfway between the two dates, the aim line is at 55%. A student at 55% in late January is right on schedule.

If the IEP doesn't give a baseline, use the average of your first three sessions on the goal, dated at the first of them.

Adding a trend line

In a spreadsheet: Google Sheets and Excel can both add a linear trendline to a chart from the chart's series options. Use a scatter chart with real dates on the horizontal axis, so the spacing between sessions is right.
On paper, the split-middle method: split the data points into an earlier half and a later half. In each half, find the middle date and the median score, and mark that point. Draw a straight line through the two marks.
Wait for enough data. A trend line through three points can swing wildly with one good or bad day. Six to eight points give a line worth reading.

Reading the graph: when to change course

Progress monitoring uses a few common rules of thumb:

Trend steeper than the aim line: the student is ahead of schedule and may meet the goal early. Plan the next step, or consider raising the goal.
Trend roughly parallel to the aim line: on track. Keep going.
Trend flatter than the aim line, or three or four points in a row below it: the student is unlikely to meet the goal on time. Change something: cue level, stimuli, how often or how long you see the student, or the activity. It's also worth asking whether the goal is the right one.

Treat these as prompts to look closer, not automatic verdicts. A run of low points after a two-week absence means something different from a slow, steady slide.

In the example, the trend line climbs about 1.8 points a week against the aim line's 1.3, and the student reached mastery about six weeks before the IEP end date.

Graphs for families and progress reports

Use one goal per graph, and put the goal in the title.
Keep the vertical axis at 0 to 100% for percentage goals, so small changes don't look dramatic.
Attach or print the graph with the progress report comment. A picture is easier for most families to read than a column of numbers.