Identify the purpose of the data collection. By focusing on the end goal, it becomes easier to see exactly what information is needed. This does not need to be written into the introduction of the sentence since there is limited space. However, it provides focus for developing what should be included. For example, if data is being collected for the purpose of seeing if a behavior plan decreases an unwanted behavior, it is obvious what type of information needs to be collected. But the opening sentence does not need to explain why the data is being collected.
Define what information needs to be collected. What needs to be collected becomes more simple to understand when the purpose of data collection is known. However, it is still necessary to define exactly what is being measured. This insures that each person taking data will be recording the same information. The sentence should explain the behavior in observable terms and not leave any room for interpretation. For example, if you are taking data on the decrease of tantrums in a student, the word tantrum should be defined.
Write the sentence. The sentence should be clear and explain exactly what is being recorded. This will include what observation should be recorded, how it is being measured and during what time periods. Using the example from above: Molly has periods of times ranging from 5 minutes to an hour where she will scream and lay on the floor. Following this would be a data sheet where there is space to record when she performs that behavior and for how long.