RICE 是四個詞的縮寫
最後的公式是：( R * I * C ) / E = RICE
Reach
代表可以接觸到的 users 量，可以用季或是月當標準單位
Impact
對公司能造成的影響
3 for “massive impact”, 2 for “high”, 1 for “medium”, 0.5 for “low”, and finally 0.25 for “minimal
Confidence
對上述猜測的信心指數，低於 50% 的話根本就不要算了
100% is “high confidence”, 80% is “medium”, 50% is “low”. Anything below that is “total moonshot”
Effort
可以用：一個人要花一個月內的多少時間才能做完來當作指標，也可以用週或是日，但很難真的估得很仔細，所以假設用週當基準，那麼一週內能做完都算 0.5，一週算 1，超過一週再往上增加
Effort is estimated as a number of “person-months” – the work that one team member can do in a month. There are many unknowns here, so I keep my estimates rough by sticking to whole numbers (or 0.5 for anything well under a month). Unlike the other positive factors, more effort is a bad thing, so it divides the total impact.
https://blog.intercom.com/rice-simple-prioritization-for-product-managers/
