Baseline
A stable measure of a behaviour — the baseline data — collected before any intervention is introduced.
A baseline, often called baseline data, is the information you collect before you do anything. It tells you where the learner actually is, not where you assume they are. Without it, you have no way of knowing whether your intervention is working, making things worse, or irrelevant.
A baseline behaviour example: before introducing a differential reinforcement plan for calling out, you might record the number of call-outs during independent work across five consecutive sessions - say 12, 14, 11, 13, and 12. That stable range is your baseline. When the count drops to 4 after you intervene, you can credit the plan rather than chance, because you know what was happening beforehand.
A usable baseline needs to be stable - that means the data aren't still climbing or falling sharply when you start your intervention. If you intervene during an upward trend, any improvement could be the natural trajectory, not your teaching. If the data are still settling, you're measuring noise.
The ethical tension with baselines is real. Waiting for stability means delaying support for someone who is struggling. The answer isn't to skip the baseline - it's to use your measurement system to detect stability faster and to understand what you're actually intervening on.
Frequently Asked Questions
What is baseline data?
Baseline data is the measurement of a behaviour collected before any intervention begins. It establishes the starting level - how often, how long, or how intense the behaviour is - so you can later tell whether your intervention actually changed it.
What is a baseline behaviour example?
Recording how many times a student leaves their seat during a 30-minute lesson across five sessions before you introduce a seating plan is a baseline. The pre-intervention counts (for example 8, 9, 7, 8, 9) are the baseline you compare later results against.
How long should a baseline be?
Long enough for the data to be stable - usually at least three to five data points that aren't sharply trending up or down. A sensitive measurement system, such as the Standard Celeration Chart, lets you reach a stable baseline faster, which matters when someone needs support now. See collecting good baseline data for the ethics of how long to wait.
What does baseline data mean in education?
In a classroom, baseline data means the level of a skill or behaviour before you teach or intervene - a pupil's current reading rate, or how often a behaviour occurs. It gives teachers an objective reference point for measuring progress rather than relying on impression.