Hokkaido, "new index" for infection status Is it difficult for citizens to understand?

When Hokkaido and Sapporo announced the number of people infected with the new coronavirus, they began to show a new "new index" that averaged the number of people infected in the last week and converted it per 100,000 population.

　The road has extended the intensive measures period to March 7, and this month 16-28 is Sapporo City. request saves us open until 10 pm in the restaurant of the whole area within. As a requirement to cancel the time saving ahead of schedule, "the average number of newly infected people in the city (total weekly) for the last week is less than 15 per 100,000 population," and the announcement is in response.

Rapid increase / decrease in the number of infected people, smoothing

　The number on the 16th was 14.4, which was below the cancellation standard. 15.3 people on the 15th. Whether or not to actually cancel will be examined in consideration of the transition of numerical values ​​and the tight medical situation.

　So far, Michi has mainly used the value obtained by converting the "number of newly infected people in the last week" per 100,000 population. The standard for requesting a state of emergency is "when the number of people exceeds 25". Even on the road alert stage, this number was used as a guide.

　The figures newly shown this time are calculated using the data of the last 13 days including the current day using the calculation method unique to Michi, and are converted per 100,000 population. Regarding this, Professor Akihiro Sato (Data Science) of Yokohama City University points out that "there is a tendency to remove drastic changes." It is said that it will be difficult to increase or decrease when the number of infected people increases sharply, such as when a cluster (group of infected people) occurs, or conversely, when the number of infected people decreases sharply. In the case of Sapporo City, the number of people on the 16th is "12.0" in the conventional method, which is less than the number of 14.4 people in the new method. The conventional method is a greater reflection of recent infection reductions.

Expert "The other way is better ..."

　Michi showed this method at a meeting of experts on the 12th, the day before he decided to extend the intensive measures period. The person in charge of the road said, "I chose this calculation method so that it would not be affected by weekends when the number of inspections would decrease."

　Meanwhile, Sapporo City side said that it had not officially grasped the new method until the 12th, "it took a while to understand because it is a new concept," said the person in charge.

　Professor Sato suggests that another method may be easier for citizens to understand if the purpose is to curb a sudden increase or decrease. "If the number of newly infected people is 15 or less per 100,000 population for a certain number of consecutive days, it will be lifted." For example, if this condition is set to "7 consecutive days", it is easy to understand that the decision is made with a grace period of 7 days. It is said to be an application of methods often used in natural disaster risk management such as flood damage .

Source: https://www.asahi.com/articles/ASP2K3FKXP2JIIPE011.html