Since the process of radioactivity was identified, experiments have been performed to attempt perturbations of the decay processes with little or no effect. It was therefore assumed that nuclear decay rates are time-independent constants of nature. Since that time, though, interesting periodicities have been identified in various experiments performed around the world, but in general, these have been attributed to various systematic effects. However, recent research has identified a possible link between solar activity and nuclear decay rates here on Earth. This is evidenced by interesting perturbations in count rates, both in experiments performed at Purdue University, and in analysis of data from experiments performed at Brookhaven National Laboratory and the Physikalisch-Technische Bundesanstalt (PTB), among others. We will examine the possible systematic causes, and see if the data suggest other external in influences as the culprit.