# Help with units and conversion

Please what are the units of currtax, co2red, taxpar, taxconstant, and the taxemint variables and parameters in MimiFUND? Are they \$/tC, \$/tC, tC/\$, tC/\$, and tC/\$?

Also, in SCC computation, how do you know what scale to use to convert SCC dollar amounts from one year to the other. In MimiFUND the amounts are calculated based on the U.S dollar value in 1995. I have seen tutorials where you multiplied by a specific value to convert to more recent dollar values. Please how do I know what scales to use for the conversions?

I understand that for equity weighting, the discount rates are computed by using the global growth rate of per capita consumption, pure rate of time preference, and the elasticity of marginal consumption ( x = x / (1. + prtp + eta * gr) ), with default values for prtp and eta, which I think only applies to the default time frame 1950-3000 -for the default module. But how do I decide on eta and prtp if I want to convert the dollar amounts (calculated in 1995 USD value) to say 2020 or 2024 values. I understand there must be an obvious answer for this, but am just not pretty clear.

Hi @pansah thanks for your interesting and question. In the SCC computation, the most important thing is to understand what dollar year the model outputs, for example it sounds like the one you are using outputs \$1995 dollars. From there you can use one of a host of online sources that account for inflation to convert to the dollar year you prefer. Government agencies often provide tools to do so, two I know of are below, but as long as you use a reputable source and cite it you should get what you need.

The `prtp` and `eta` values are independent of the dollar year that you choose to present your final results in, so those can be chosen based on your decisions about how to parameterize your discount rates, and any conversion between dollar years happens on the back-end with multiplication by a scalar.

Also, as an aside, the equation you present above is general to Ramsey discounting, not just to equity weighting. Equity weighting uses the Ramsey discounting framework – from Wikipedia

Equity-weighting is often implemented in this framework, but is not defined by the equations above, and is best described in literature published by folks like Dr. David Anthoff.