No, the title of this post isn't about the usual metric system, kilometers vs miles, liters vs quarts, etc. What I want to talk about is setting up you do magically so you can measure the results. Clearly, this applies more easily to thaumaturgy than theurgy, but it can be done in both.
I lightly touched on measuring results in the last post, on curses, where I mentioned that I had not set up any way to measure my first curse, but the second one was more easily measured - the Beltway Shooters got caught and police started getting FAR more clues starting that day (and for the protection spells I did with that, none of the rest of the attacks took place in my county).
If you can't/don't measure your results, you don't know if the spell worked at all, worked some, worked a lot, failed totally. And you need to know these things so you can improve the results of your magic.
I still say that if you do a ritual for peace for a specific period of time, and war breaks out instead, then your ritual probably failed. If you do a protection spell on your home and it's followed by a break in two weeks later, then something went wrong.
Your Book of Shadows is a lab notebook. You note exactly what you did, what you wanted, how you did it, etc. You then note all the results. And then you see what could be tweaked.
About 15 years ago I did a working to help our home business get more business, focused on improving our marketing, our success in getting word out to potential clients about how we could help their businesses. It worked, we got TONS of business in a few months. BUT it turned out we got more business than we could handle, we lost some clients, got sued by one of them that we hadn't vetted well enough, etc. Not the best magical result. A costly lesson, but one that I know about because I followed up on results.
Doing a ritual to heal the earth? Focus on a specific area where you can check stats on results. Maybe compare number of days with air pollution warnings to the same time last year. Or number of days beaches are closed. Maybe number of people involved in stream cleanup, or percents of garbage recycled vs sent to landfill over time.
Metrics are you friends. Measuring results lets you modify what you are doing to get better results.
Go forth and be wonderful!