The government, and Mr. Pesquera in particular, was widely criticized for undercounting the number of people who died on the island as the power outage stretched for months, causing deaths from diabetes and sepsis to soar. Many people died from lack of access to hospitals, or because there was no power to run the machines they used to breathe.

Even in the face of mounting evidence from funeral directors around the island, Mr. Pesquera had insisted that unless doctors certified on a patient’s death certificate that the storm contributed to the person’s death, the person would not be counted.

After a New York Times analysis in December showed that even the preliminary data from the Demographic Registry of Puerto Rico indicated that deaths had risen by 1,052, Gov. Ricardo Rosselló hired George Washington University’s school of public health on a $305,000 contract to conduct an analysis. The report, now three months overdue, is expected to be released at the end of the month.

“We definitely acknowledge this is a realistic estimate,” Pedro Cerame, a spokesman for the Puerto Rican government’s Federal Affairs Administration, said of the numbers in the report to Congress. “We don’t want to say it out loud or publicize it as an official number. The official number will come, and it could be close.”

The final version of the report, released Thursday, hedged the language to say that the additional deaths “may or may not be attributable” to the storm; the 1,427 figure was also deleted from a chart.