The Hawthorne effect is the human tendency to alter behavior - for example, to overperform - when we know we are being observed. In the context of a LENA Day, the tendency would be for the adult to talk/interact more than normal, thereby creating results that are difficult to repeat or sustain, much less to improve upon. Depending on how you are using your SP data, whether you are comparing it against other LENA program data, and what the subjects' expectations are, you may wish to correct for the Hawthorne effect. Below is some guidance.

In an analysis of our normative data, comparing the first recording to the remaining recordings within family, we saw an 8% elevation in Adult Word Counts for the first recording, and a 10% elevation in Turns, both of which were statistically significant. Further, we found that 44% of our normative sample had 15% elevations on words, and 45% showed 10% elevation on turns. 

We know that there are two things that could influence parents to talk more than they typically do on their first recording in LENA interventions: 1) novelty of the recorder, 2) knowing their reports will be seen by an intervention provider or evaluator and wanting to perform well due to social pressure. In deciding how to handle your own data, consider that our normative participants would have been influenced only by the first issue (novelty) because they never saw reports.