There are two forms of implementing spacing in spaced repetition. The first form is absolute spacing. Absolute spacing is the measurement of all the trials within the learning and testing periods. An example of this would be that participants would study for a total of thirty trial periods, but the spacing of these trials can either be expanding or uniform. The second form is called relative spacing. Relative spacing measures the spacing of trials between each test. An example of this would be if the absolute spacing was thirty, participants would either have expanding intervals (1–5–10–14) or uniform intervals (5–5–5–5–5–5). This is important in measuring whether or not one type of repetition schedule is more beneficial than the other.