State health officials reported that 5,251 Arizonans have been tested positive for COVID-19. Another 21 people have died from the disease, bringing the state’s total to 208 as of Tuesday.

This is the greatest number of deaths the state has reported in a single day, topping the previous high of 19 this past Friday.

Models, such as the University of Washington’s IHME Covid-19 Model, and a machine learning-based model by MIT Data Scientists use this number for their projections.

Youyang Gu, one of the people behind the MIT model said that the state’s daily death number is used as the “hard truth,” or the most reliable number coming out of state COVID-19 reports. The University of Washington’s model, one that is being monitored by state officials, extrapolates the hospital resources a state may need to combat COVID-19 based solely off the reported death number.

The total number of deaths reported by the state is not a number that most experts would question, but there might be an interesting catch. Numbers reported by the Department of Health in the morning do not necessarily reflect what occurred the day before.

The state dashboard paints a different picture than the daily reported death numbers. For one thing, the timeline chart on the COVID-19 deaths dashboard ends on April 19. The chart also shows eight deaths on April 17, the day that was previously considered the “peak” day for deaths until today. The chart instead shows Tuesday, April 11, when the state reported 14 people as had died from COVID-19, as the actual peak death day.

The state Department of Health confirmed this discrepancy. A spokesperson told us that “As local public health becomes aware of deaths for COVID-19 cases, this information is reported and becomes included in the dashboard numbers.

However, these deaths may have occurred over previous days. Therefore, the "New Deaths Reported Today" did not necessarily occur on that (or the prior day).

The "COVID-19 Deaths by Date of Death" shows the actual date of death. During public health investigations, it may be known that an individual has passed away; however, the precise date of death may be currently unknown. The overall count includes all known COVID-19 deaths. The Deaths by Date of Death graph can only display individuals with a known date of death.”

The department’s statement is confirmed by the data. When placed on a timeline, the “Daily Reported COVID-19 Deaths,” has several dramatic rises that are preceded by a series of days with more stable numbers.

These dramatic rises are also found right after times when the “Actual Assigned Death Date” is larger for several consecutive days. This suggest that the state is receiving data in clumps that they are then backfilling with further investigation.

So why would this matter?

We’ve been told by Arizona state health officials that they are using projections from the University of Washington Model in their decision making when it comes to allocation of healthcare resources. This model, which has faced criticism, recently adjusted upwards from a projected total of 267 deaths in Arizona to 480 based on Friday’s number.

Once both the MIT model and the University of Washington model take in today’s reported spike, they will likely once again adjust upwards, and state health officials, as well as those that will decide when it is safe to open up Arizona’s economy once again.