Examining the effect of social distancing on the compound growth rate of COVID-19 at the county level (United States) using statistical analyses and a random forest machine learning model.

OBJECTIVES: The goal of the present work is to investigate trends among US counties and coronavirus disease 2019 (COVID-19) growth rates in relation to the existence of shelter-in-place (SIP) orders in that county. STUDY DESIGN: This is a prospective cohort study. METHODS: Compound growth rates were calculated using cumulative confirmed COVID-19 cases from January 21, 2020, to March 31, 2020, in all 3139 US counties. Compound growth was chosen as it gives a single number that can be used in machine learning to represent the speed of virus spread during defined time intervals. Statistical analyses and a random forest machine learning model were used to analyze the data for differences in counties with and without SIP orders. RESULTS: Statistical analyses revealed that the March 16 presidential recommendation (limiting gatherings to ≤10 people) lowered the compound growth rate of COVID-19 for all counties in the US by 6.6%, and the counties that implemented SIP after March 16 had a further reduction of 7.8% compared with the counties that did not implement SIP after March 16. A random forest machine learning model was built to predict compound growth rate after a SIP order and was found to have an accuracy of 92.3%. The random forest found that population, longitude, and population per square mile were the most important features when predicting the effect of SIP. CONCLUSIONS: SIP orders were found to be effective at reducing the growth rate of COVID-19 cases in the US. Counties with a large population or a high population density were found to benefit the most from a SIP order.

The difficulties in constructing a common denominator for peer review in general practice.

A helpful analysis of clinical events in general practice would be to show a doctor how his opinion compares with the use of the same opinion by other doctors. For such a comparison a common denominator, which is a measure of clinical opportunity, is required. The population of patients cared for by a doctor can be used for this purpose and this paper describes a method which uses a computer to calculate the share of a known practice population that each doctor has cared for. The computer produces details of consultations, set out in square tables, of those registered with each doctor and those seen by each doctor.

Do patients who move to a new town consult their doctor more often?

A study was conducted to measure any difference in the consultation rate of patients from two new town housing estates compared with patients from the rest of the practice. Patients from the new estates consulted 15% to 20% more than those in other areas, but newly registered patients showed no difference compared with the indigenous population. It is suggested that patients who chose to move to new town rented accommodation bring with them a more casual attitude to the general medical services.

Estimating list inflation in a practice register.

The reason why patients were incorrectly registered in an age-sex register was studied. Whereas underregistration was caused by patient delay in registering with a doctor, the much greater number of overregistered patients were thought to be there largely because of administrative delays in removing their names from the register. It is suggested that it would be possible for the software of a computer system in general practice to correct the population size and structure for estimated list inflation.

Behavior and the Crustacean Molt Cycle: Changes in Aggression of Homarus americanus.

The phase of the molt cycle affects dominance status and the performance of agonistic acts in individual juvenile lobsters (Homarus americanus). Lobsters in the midphase of proecdysis are more aggressive than those in intermolt; the latter are more aggressive than lobsters in early or late proecdysis and those in postecdysis.

Consultation patterns in a general practice.

A study from the Oxford Community Health Project is reported on the effects on consultation rates in general practice of patients' age, sex, date of registration, address, and usual doctor. The impact on consultation rates of accessibility of surgeries and availability of doctors is examined when the variables are controlled, and the importance of these factors is discussed in relation to planning primary medical care.

Thyroid function in euthyroid Jamaicans

Thyroid function has been investigated in 32 hospitalized euthyroid Jamaicans. The in vivo investigations performed were measurement of 2«, 4 and 24 hr thyroidal uptake of 131I, thyroidal and renal clearances of radioiodide, absolute iodide uptakes and, in 6 subjects, radiothyroxine turnover studies. Thyroxine binding globulin and prealbumin capacities were measured in a small number of cases. Results obtained in all these investigations agreed well with those found in temperate climates and are at variance with previous finding of low 24 hr thyroidal uptakes of 131I in euthyroid Jamaicans, associated with a normal serum protein-bound iodine.(AU)

Reassessment of thyroid function in euthyroid Jamaicans

In 1964 Goldberg et. a.l reported the results of a thyroid function study in a large group of normal Jamaicans. Very low 24 hour thyroidal uptakes of I131 were obtained, the mean being 13.8 percent of the dose. In view of these findings thyroid function was reassessed in 32 euthyroid Jamaican subjects. Investigations performed included, estimation of plasma inorganic iodide, 2, 4, and 24 hour thyroidal uptakes of radio iodide, absolute thyroidal iodide uptake and thyroidal and renal clearances of plasma iodide. Results obtained in all these investigations agreed well with those found in temperate climates and are at variance with the findings of Goldberg et al (AU)