How to collect baseline data for an IEP goal
By the IEP Atlas editorial teamLast updated
Short answer
Collect baseline data before you write the goal. Define the behavior so two people would score it the same way, pick the measure the goal will use, and take at least three probes under the goal's conditions. Report the median and the range in present levels. That number becomes the starting point every later probe is compared to.
A baseline is the student's current performance on the exact skill the goal targets, measured the way the goal will be measured. Without one, a target is a guess and a progress report is an opinion.
Most baseline problems come from one of three gaps. The behavior was never defined. The measure does not match the goal. Or there is only one data point. The steps below close all three.
Why the baseline comes first
The goal's target should come from the baseline and the growth you expect, not from a default like 80%. The IEP must say how progress toward each goal will be measured and when reports go home.[1] A baseline taken the same way is what makes those reports mean something.
It also protects the student. If a goal is set too low, the student can meet it without real growth. If it is set too high, the team may decide an approach failed when it was working. A clear starting number keeps that decision honest.
Step 1: Define the behavior
Write a one-sentence operational definition of the behavior. It should be clear enough that two adults watching the same student would mark the same thing.
- Too loose: "Stays on task."
- Clear: "Eyes on the assigned material or writing, with no more than 5 seconds looking away."
- Too loose: "Asks for help appropriately."
- Clear: "Raises a hand or uses a help card and states what part is hard, within 2 minutes of getting stuck."
Test the definition before you collect. Have a second adult observe with you for one session and compare marks. If you disagree on more than one or two marks, tighten the wording.
Step 2: Pick the measure the goal will use
The baseline and the goal must use the same unit. Choose the unit that fits the behavior first, then the data sheet.
| What you want to know | Measure | Data sheet |
|---|---|---|
| How quickly the student starts | Latency in seconds | Latency data sheet |
| How long the student stays engaged | Duration in minutes | Duration data sheet |
| How often the student uses a skill when the chance comes up | Opportunities | Opportunity data sheet |
| How well the student does scored items | Percent accuracy | Accuracy data sheet |
| How fluently the student reads | Words correct per minute | Reading fluency sheet |
If you are not sure which fits, the measurement guide explains each type with goal examples.
Step 3: Use the goal's conditions
Collect the baseline under the conditions the goal will name. Use the same kind of materials, the same setting, and the same level of help. If the goal says "given an unpracticed passage at grade 4," the baseline passages must be unpracticed grade 4 passages.
Record the support you gave. If the student only started work when you stood nearby, note it. That is useful information, but it is not an independent baseline.
Step 4: Take at least three probes
One probe can catch a bad morning, a fire drill, or a hard passage. Take at least three probes on different days. For behavior that changes a lot from day to day, take five.
Repeated short measures over time are the core of progress monitoring.[2] The baseline is simply the first few points on that graph. Keep each probe short and the same length, so the scores can be compared.
Step 5: Report the median and the range
Order the probes from lowest to highest and take the middle one. The median is less affected by one odd day than the average. Report the range next to it.
For example, latency probes of 240, 95, 180, 400 and 150 seconds give a median of 180 seconds. The range is 95 to 400 seconds. A wide range like this tells the team the behavior depends on something, such as the subject or the time of day. That is worth a sentence in present levels.
Step 6: Write it into present levels and the goal
Put the baseline in present levels with the date, the conditions, and the measure. Then build the goal from it. A strong goal names the starting point and the target in the same unit, so anyone can compare the next probe with the first.
For worked wording, see these present levels examples. To check the finished goal for vague parts, paste it into the goal checker.
When the baseline is zero or perfect
A baseline of zero is real data. It often means the skill is not there yet, or the task is too hard as written. Before you set a goal, try an easier version of the task. A goal built from a zero baseline is hard to set well, because there is no growth to project from.
A perfect baseline means the skill is already mastered under these conditions. Make the conditions harder, such as a new setting or less help, or pick a different skill. Do not write a goal the student has already met.
Mistakes that make a baseline useless
- Using last year's data. If it is more than a few weeks old, collect again.
- Measuring a different task. A spelling test is not a baseline for a writing goal.
- Mixing levels of help. Mark which probes had prompts and which did not.
- Rounding to a nice number. Report what you measured, not what sounds right.
- Skipping the date. A baseline with no date cannot anchor a progress graph.
Frequently asked questions
How many data points do I need for a baseline?
At least three, taken on different days under the same conditions. Use five for behavior that varies a lot. Report the median, not the best or worst day, so one unusual session does not set the goal.
Can I use the median instead of the average?
Yes, and for small sets of probes it is usually the better choice. The median is the middle score. One very high or very low probe moves an average a lot but barely moves the median.
What if I have no time to collect baseline data before the meeting?
Take short probes during regular instruction in the two weeks before the meeting. Three five-minute probes are enough for most academic skills. If you truly have none, the team can agree to collect it in the first weeks and add it by amendment.
Use it in IEP Atlas
- Baseline in the IEP glossary
- Measurement types for IEP goals
- Latency data sheet
- Duration data sheet
- IEP goal bank
Related guides
- How to write IEP goals: a step-by-step method with examples
- Present levels (PLAAFP) examples that lead to measurable goals
- Setting a realistic annual target from baseline and growth rate
- IEP goal examples: measurable goals for every area
Sources
- 34 CFR §300.320: Definition of individualized education program, Legal Information Institute, Cornell Law School
- Progress Monitoring: Data & Goal Setting, National Center on Intensive Intervention
Written and checked by the IEP Atlas editorial team under our editorial policy. This guide describes general practice and federal rules. It is not legal advice; your state may add requirements, and the IEP team makes the decisions for each student.