Every day from March 26 to May 31 inclusive, NYT has reported more cases than USAFacts. On March 26, NYT reported 495 more cases than USAFacts, and by May 31, this lead had grown to 19,736 cases.
The Pearson correlation between the number of cases reported by NYT and USAFacts was 0.9999990.
NYT vs. JHU
Every day from March 25 to May 31 inclusive, NYT reported more cases than JHU. During this time, the lead NYT's case count has over that of JHU has grown from 2,686 on March 25 to 8,592 on May 31.
The Pearson correlation between the number of cases reported by NYT and JHU was 0.9999996.
USAFacts vs. JHU
Every day from April 5 to May 31 inclusive, JHU has reported more cases nationally compared to USAFacts. On April 5, JHU reported 1,690 more cases nationally than did USAFacts, and this value grew to 6,602 more than USAFacts by May 31.
The Pearson correlation between the number of cases reported by USAFacts and JHU was 0.9999987.
Comparing the number of deaths across the four trackers
Fig. 3 below shows the total number of COVID-19 deaths in the United States reported by the four trackers. As is evident from this figure, COVID Tracker (blue line) has reported significantly fewer deaths than any of the other three trackers (orange, gray, and yellow) for some time. The other three trackers' death counts have tended to cluster more closely together.