Basing Policy on Empirical Evidence

The use of empirical evidence to influence or determine policy is one of the major challenges found in countries at the bottom of the development ladder.
What is the evidence so far about the transmission of Ebola? I am told by one of our erudite specialists in the field that over 99% of the cases of infected people report that they contracted it through tending to, visiting, transporting, living with people sick from Ebola; or health workers treating sick patients. The earlier worry that bush meat may have been the culprit – known to be hosts of the virus – is hardly mentioned now, and rightly so. This is not to say all caution should be thrown to the wind. Rather good sense dictates that the focus should be on getting people to refrain from touching bodily fluids of sick people.
Banning markets or closing them on certain days would give some people a feel-good satisfaction, but without evidence that infections occur in markets we would be fighting the wrong battle. Indeed if the virus was being spread in market places by now a third of the country would be gone.
On the other hand, there are many anecdotes about the ineffectiveness of quarantined houses and of the police assigned to keep the houses quarantined, that would fill a joke book on the fight against Ebola. Hence if we rely on empirical evidence, we would use our soldiers to reinforce the quarantined houses, and to ensure that there are responses to 117 calls – assuming the BBC and other reports of no, or slow response are true.
On another note, as a policy maker the first thing you learn is that almost all policies produce side effects that in turn generate unintended consequences. Hence one must anticipate them and compensate or mitigate them. As we close down markets, shut down small businesses, cordon off districts, we should be aware of the short and long term economic and welfare effects on the country and people; and we should take measures to compensate or mitigate these ripple effects (and not just food supplies). Failure to do so may generate unintended consequences that are harder to control.