Thanks for this.
While the website shows a R rate, I cannot see an explanation of how it calculated.
It mentions "Calculated with a 4-day ratio"; but what is this ratio?
Covid test numbers vs new cases detected?
Ro represents, on average, the number of people that a single infected person can be expected to transmit that disease to.
Reff is the actual" or "effective" rate that vaccinations is actually occurring. ie If there are public health measures (ie masks, social distancing, lockdowns) in place and/or vaccinations Reff will be less that Ro.
The Reff you see reported is actually an "estimated" Reff from cases as the exact number of infections is not ever known with Covid. In calculating it you could just go day by day. ie Take today'number of cases and divide by yesterdays. More than 1 is increasing. Less than 1 is decreasing. Health authorities want Reff to be less than 1 so that infections will over time decrease.
However only using a day by day number to calculate Reff would lead to wild fluctuations. So normally it will be smoothed
by using a rolling 4 day average, or a 7 day average etc. In addition in more detailed estimates a k factor will be used to allow for variance. As different sources will calculate the Reff differently you will see different numbers generated due to what method they use to calculate the Reff.
In addition when case numbers are low Reff will not be accurate as again the number can bounce around too much to be reliable.
For more explanation see
What are k numbers, and how do they explain COVID superspreading?
Dr Nick Coatsworth suggests the R number in a densely populated suburb with high rises will have a different R number to a lower density suburb in the same city (see:
What is the R number and why is it important?)
Yes the Ro would be higher where a person can infect more people.
ie So a person in a highrise would potentially be able to mix with more people and so they would potentially be in contact with more people in a given infectious period and so the Ro would be higher.
Similarly a population cohort with larger family sizes would have a higher Ro than a cohort with smaller family sizes.