Most of my analyses with this data set have been with time series of area average precipitation anomalies for large regions. This sort of averaging is effective at picking out climate variability signals related to ENSO. An example of this sort of analysis is the time series equatorial Pacific island precipitation, plotted below with equatorial Pacific SST anomalies for the period 1890-1992.

Equatorial Pacific rainfall and cold tongue temperature anomalies, 1890-1992

Documentation of the data

Reference:
Eischeid, J. K., C. B. Baker, T. R. Karl, and H. F. Diaz, 1995: The quality control of long-term climatological data using objective data analysis. J. Appl. Meteor., 34, 2787-2795.