# How to score/measure the change in a time series from t-x,…t-1 to t0 (Relative change)

I think about having data such as:

Time   1   2   3   4   5   6   7   8   9 ... n

Set1  12  13  13  23  26  27  40  13  13
Set2   2   3   4   2   4   3  10  12  11
.
.
.
Setn ...


All datasets are equivalent in terms of the meaning what a sudden (relative) change in values indicate. Means when in set1 is a change from 13 to 23 it indicates the same as when there is a change from 3 to 10 in set2. It only depends on the relative change of the actual t0 to the average of the past x periods.

My question is what is the best way to quantify such change? My goal is to have a value in each period for each dataset that indicates the change. This value should be comparable to the other datasets. Means when I have a change from 13 to 23 the value should approximately similar to a change from 3 to 10.