I guess it’d be interesting if you could measure the drop in undeclared income by seeing places that increased their turnover as electronic payments became common. Although because covid was a big driver for that in many places, and disrupted all the expectations for business, demand, costs etc it might be hard to pick apart.
Tbh, almost all oven thermostats are not accurate for the actual temperature of the oven. Like, they probably are measuring 170 accuretly, but the thermostat is in the very back top corner and the temperature in the middle shelf is 15 degrees off.
People who are keen on baking, roasting meat etc where temperatures are important often recommend getting an oven thermometer so you can see the real temperature.