It doesn't seem possible to fully measure / report the effect of a climate change policy in a short time, some of the impact will be easy to find (the budget cost of it, the direct job created by the policy, etc....) but the secondary effect will be really hard to measure precisely ( since it's an inferred (secondary) effect; it will be really wilder and will depend a lot from the methodical choices...so it could have some argument around this ...)
and to finish, usually the impact on environment (especially on climate) need long terms measurement (to allow statistical analysis )
i mean here , that if you want to asset the entire effect of the policy, you will have to gather lot of data from different sphere (climate, environmental, economical, social...)
the mean problem here is that the effect of the policy will not apply to the sphere in the same time and with the same speed
example: the effect on climate will be very progressive, and since the climate depend a lot from the season, you will have to gather date over some seasons to be able to make comparison
the effect on economical will have a direct effect on budget, then a first effect on the workforce when people will be hired to applied the policy, and then you will have secondary effect when entreprise will work for the policy or apply it
like was saying ruxandra, the measure will depend a lot of the model you take, since by example you won't be able to measure exactly even the first economical effect on workforce (so for the second one....)
the "solution" is to reduce the range of the measurement , if you just measure the CO2 rejection in the atmosphere, you will be able to gather more easily those type of information, but after you will have to determine if you just want to focus on this point and doesn't take in account the rest of the policy effect...
it depends on you to choose from feasability of the study and realistic impact measurement