Auto- and cross-correlation methods, when applied to discrete events, can determine periodicity and correlation times within and between event train sequences. However, if the number of available events for analysis is too few, the correlation techniques yield ambiguous and insufficient results. Here we report a technique based on measurements of phases of event times that could detect the periodicity even among very few discrete data points. The results are demonstrated on in vitro neuronal spike time data, and are found to be highly contrasting when compared with the correlation techniques. The technique could become invaluable, for example, for treating in vivo spike time records that often last very short duration, or for determining short timescales in discrete biophysical experimental data.