The authors of this study investigated changes in the adherence to non-pharmaceutical interventions in the US during the months of April-November. The researchers measured adherence by analysing survey responses from the Coronavirus Tracking Survey (CTS), which was administered from April 1, 2020 to November 24, 2020. The participants of this study were recruited from the Understanding America Study and consisted of residents from all U.S. Census regions. Participants of the study completed the CTS survey every 14 days. The researchers of the study created a non-pharmaceutical intervention adherence index (NPI) which ranged from 0 (low adherence) to 100 (high adherence). The study showed a considerable decrease in the NPI index from 70 in April to 50 in June, followed by an increase to 60 in November. Adherence to individual non-pharmaceutical interventions decreased the most, though there was an increase in mask wearing. The results of the study have implications regarding the public health messaging around NPIs, and the concept of pandemic fatigue. The authors suggest future work is needed regarding methods to combat pandemic fatigue.