1. Cases per 100k a factor we take into account - and it is often quoted - but it’s not only one. We also look at test positivity rate. And rely on analysis of public health experts as to whether there is clearly identifiable source of outbreak/potential community transmission https://twitter.com/c4ciaran/status/1301414069895925761

2. If, eg, you have high rate per 100k in an area but confidence that it’s associated with identified outbreaks that are being contained, wider restrictions may not be necessary. This was case recently in Tayside/Coupar Angus food processing plant outbreak.../

3. Heightened concern in @NHSGGC - particularly 3 affected council areas - is that cases appear to be linked to multiple, smaller unconnected clusters with potential community transmission, hence need for wider restrictions to stem spread.../

4. I agree it would be much easier in both decision-making and public communication if there was a single, simple formula/threshold, but it’s more complicated. It requires expert analysis and judgment and tough, often ‘on-balance’ decisions.