I think you may have mixed the terms SPR (stack to pot ratio) and implied odds.

SPR is self explanatory. Implied odds are in reality pot odds with future bets implied in the calculation.

Things to consider when estimating implied odds are:

- Strength of villains hand

- How obvious your draw is (dependant upon villains skill level)

- Villains tendencies

- Number of opponents

- Position

- Your range

- Your image

- Etc, etc