It is well known that we can't directly compare one state to another purely based on the number of confirmed cases due to different population sizes. Statistics used in the spatial representation of aggregated (e.g., county or state-level) disease risk data include the infection rate (IR), standardized infection ratio (SIR), and the weekly local risk (WLR). The IR is the number of cases and the population divided by the population in the area. The SIR is the classic statistic used in representing spatial patterns of disease distribution. It standardizes the data by re-expressing them as the ratio between the observed number of cases and the number that would have been expected in a standard population. It is the infected cases per population divided by country infected cases per population. The WLR is another risk measure, which is calculated using the average number of new cases in the past week divided by the population in the area. The WLR gives you a way to assess the state's current risk level compared to other states.
Now let us compare the IR, SIR, and WLR among all the states after adjusting the population's effect. In the early stage of the pandemic, New York and New Jersey have the highest IR/SIRs.
By April 21 (2021), WLR is increasing dramatically for Michigan, making it the most risky states in the US. Pennsylvania, Delaware, Maine and Colorado are also faced with increased risk. New Jersey, instead, has seen consistently decreasing risk in terms of WLR.
By February 7 (2021), WLR are decreasing for most states, except New Jersey, which still demonstrates no significant trend in weekly local risk. For IR, Arizona surpassed Tennessee and become the state with highest IR. Georgia and Texas also increased fast in IR and surpassed California, reaching the third and fourth highest in IR. For SIR, Arizona, Texas, North Carolina, New Jersey, and New York have increasing SIR. Arizona and Tennessee have leading SIR, higher than 130%, which indicates the local infection risk in these two states are significantly higher than the rest of the country.
By January 22 (2021), for WLR, Arizona still has the highest weekly infected per population. Most states are having decreasing trend in WLR last week, indicating an better situation across the country. For IR, Tennessee, Illinois, and Arizona have the highest cumulative infected cases per population. For SIR, Arizona, Georgia, New York, and North Carolina are having obvious increasing trend, which indicates the spread in these states are faster than other states now.
By January 16 (2021), for WLR, Arizona still has the highest weekly infected per population. Most states are having increasing trend in WLR last week, indicating an overall worsening infection across the country. For IR, Tennessee, Illinois, and Arizona have the highest cumulative infected cases per population. For SIR, Arizona, North Carolina, New York, and California are having obvious increasing trend, which indicates the spread in these states are faster than other states now.
By January 8 (2021), for WLR, Arizona now has the highest weekly infected per population. Most states except Kansas are still increasing in WLR last week, indicating an overall continuing worsening infection across the country. For IR, Tennessee, Illinois, and Arizona have the highest cumulative infected cases per population. Arizona surpassed Illinois became the second hightest. For SIR, Arizona, New Jersey, New York, and California are having obvious increasing trend, which indicates the spread in these states are faster than other states now.
By January 1 (2021), for WLR, California now has the highest weekly infected per population. Most states are still increasing in WLR last week, indicating an overall continuing worsening infection across the country. For IR, Tennessee, Illinois, and Arizona have the highest cumulative infected cases per population. California surpassed Michigan became the eighth hightest. For SIR, Arizona, Georgia, Pennsylvania, New York, and California are increasing, which indicates the spread in these states are faster than other states now.
By December 17, for WLR, Tennessee now has the highest weekly infected per population. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Illinios, and Tennessee have the highest cumulative infected cases per population, among which Tennessee surpassed Illinois and came to the second place. For SIR, Tennessee, Ohio, Pennsylvania, and California are increasing, which indicates the spread in these states are faster than other states now.
By December 4, for WLR, Minnesota now has the highest weekly infected per population. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Illinios, and Tennessee have the highest cumulative infected cases per population. For SIR, Ohio, Pennsylvania, and Michigan are increasing, which indicates the spread in these states are faster than other states now.
By November 27, for WLR, North Dakota still has the highest weekly infected per population. South Dakota has declined a lot in this week. New Mexico and Montana have a noticeable decreasing trend. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Illinios, and Tennessee have the highest cumulative infected cases per population. Texas exceeded Georgia in this week. Ohio exceeded New York. For SIR, Ohio, Illionois, Wisconsin, Pennsylvania, and Michigan are increasing, which indicates the spread in these states are faster than other states now.
By November 19, for WLR, North Dakota still has the highest weekly infected per population. South Dakota has the second higest weekly infected per population. They both have a relative stable trend. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Illinios, and Tennessee have the highest cumulative infected cases per population. Illinois exceeded Tennessee in this week. For SIR, Illinois, Wisconsin, Ohio and Michigan have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By November 12, for WLR, North Dakota still has the highest weekly infected per population, with an increasing trend. South Dakota has the second higest weekly infected per population. Iowa has a noticeable increase in this week. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Illinios, and Tennessee have the highest cumulative infected cases per population. Illinois exceeded Florida in this week. For SIR, Illinois, Wisconsin and Ohio have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By November 6, for WLR, North Dakota still has the highest weekly infected per population, with an increasing trend. South Dakota has no increasing trend for this week, but it still has the second higest weekly infected per population. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Florida, and Tennessee have the highest cumulative infected cases per population. In addition, Wisconsin, Illinois, and Ohio grows relatively fast in infection per population. For SIR, Illinois, Wisconsin and Ohio have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By October 29, for WLR, North Dakota still has the highest weekly infected per population, with an increasing trend. South Dakota caught up with North Dakota in this week. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Wisconsin, Florida, and Tennessee have the highest cumulative infected cases per population. Wisconsin exceeded Florida and Tennessee in this week with a persistent fast increading trend and became the leading state among all other states. In addition, Wisconsin, Illinois, and Ohio grows relatively fast in infection per population. For SIR, Illinois, Wisconsin and Ohio have increasing SIR, representing their increasing risk compared to the average risk of the whole country. Wisconsin exceeded Florida and Tennessee, and reached the first place in SIR this week.
By October 22, for WLR, North Dakota still has the highest weekly infected per population, with an increasing trend. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. North Dakota and South Dakota have worrisome spread in particular. For IR, Wisconsin, Florida, and Tennessee have the highest cumulative infected cases per population. Wisconsin exceeded Arizona in this week with a persistent fast increading trend. In addition, Tennessee, Illinois, and North Carolina grows relatively fast in infection per population. For SIR, Illinois, Wisconsin and Pennsylvania have increasing SIR, representing their increasing risk compared to the average risk of the whole country. Wisconsin exceeded Arizona and Georgia, and reached the third place in SIR this week.
By October 15, for WLR, North Dakota still has the highest weekly infected per population, reaching its new peak. South Dakota has very similar WLR to that of North Dakota. Most states are still increasing in WLR last week, indicating an overall worsening infection across the country. For IR, Louisiana, Florida, and Tennessee have the highest cumulative infected cases per population. Tennessee exceeded Arizona in this week. For SIR, Tennessee, Illinois and North Carolina have increasing SIR, representing their increasing risk compared to the average risk of the whole country. Tennessee exceeded Arizona in this week.
By October 8, for WLR, North Dakota still has the highest weekly infected per population, reaching its new peak. Most states are still increasing in WLR, indicating an overall worsening infection across the country. For IR, Louisiana, Florida, and Arizona have the highest cumulative infected cases per population. Tennessee exceeded Georgia in this week. Illinois exceeded New York and therefore became the state with 7-th highest infected per population. Also, North Carolina exceeded California in this week. For SIR, Tennessee, Illinois and North Carolina have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By October 2, for WLR, North Dakota remains highest with a slight dip in the past week,followed by South Dakota and Wisconsin which have a worrisome upward trend. In addition, Montana and Nebraska have also seen fast increase in WLR. For IR, Illinois exceeded New Jersey and became the state with 8-th highest infected per population. And Tennessee is approching Georgia, and is likely to exceed Georgia in the following week. For SIR, Tennessee, Illinois and North Carolina have increasing SIR, representing their increasing risk compared to the average risk of the whole country. The trend of Illinois and Tennessee in IR also resembles that in SIR.
By September 25, for WLR, North Dakota still has the highest weekly infected per population, with a worrying upward trend. Most states are still increasing in WLR, indicating an overall worsening infection across the country. For IR, Louisiana, Florida, and Arizona have the highest cumulative infected cases per population. For SIR, Tennessee, Texas, Illinois and North Carolina have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By September 17, for WLR, NorthDakota still has the highest weekly infected per population. Most states changed from decreasing to increasing in WLR, indicating an overall worsening infection across the country. For IR, Louisiana, Florida, and Arizona have the highest cumulative infected cases per population. For SIR, Tennessee, Illinios, and North Carolina have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By September 10, for WLR, North Dakota has the highest weekly infected per population. Over the past few days, the WLRs for SouthDakota, Iowa, and Alabama decreased substantially but are still very high among the states. Wisconsin and Oklahoma have increasing WLR, demonstrating increased risk and faster spread. For IR, Louisiana, Florida, and Arizona have the highest cumulative infected cases per population. For SIR, Tennessee, Illinois and North Carolina have increasing SIR, representing their increasing risk compared to the average risk of the whole country.
By August 28, under IR, Louisiana, Florida, and Arizona have the highest infected per population, followed by fastly increasing Georgia. For WLR, Iowa leads the country with an exponentially increasing weekly infected per population, 34 per 100K were confirmed in the past week, closely followed by 31 per 100K population in North Dakota. Alabama and Kansas also exhibit increasing trend and need attention.
By August 21, WLR increased rapidly in Mississippi, Alabama, Oklahoma, and South Carolina, indicating faster spread in the past week. Louisiana, Florida and Arizona are the top 3 states in terms of cumulative infected cases per population (IR). For SIR, Georgia, California, Texas, Tennessee are increasing, suggesting higher infected density as time goes compared to the average level for the whole country.
By August 15, the overall trend of the SIR decreases except for Lousiana, Florida, and California, which may indicate the spread of COVID-19 in these states is worrisome.
By August 5, the overall trend of IR and SIR decreases in Florida, Mississippi, and Louisiana, which may indicate the spread of COVID-19 in Florida, Mississippi, and Louisiana are under better control than the last week.
By July 29, the top three states with the highest WLR are Florida, Mississippi, and Louisiana, which indicates a resurgence of COVID-19 in these states and calls for attention.
By July 23, the IR and SIR in Louisiana and Arizona exceed New York and New Jersey. Meanwhile, Florida increases fast in IR and SIR. The WLR also suggests that New York and New Jersey are not in the highest risk currently.
Please also check Growth Rate app for the top 12 states in cumulative infected counts. Are you interested in finding the risk of your state or county? The interactive map in our shiny app provides a real-time 7-day rolling forecast of the WLR at both the state level and county level. Check it out to see your community's current and predicted risk level!