**Efficiency**Is a measure of the cost per experience of a training method, factoring in **opportunity cost** (the amount of profit that was sacrificed by pursuing the training method instead of spending the same amount of time earning money). Efficiency is often used in the context of evaluating, based on how valuable you perceive your time to be, two different methods to train a skill for which their experience per hour and profit per hour rates are known or calculated. If one method gives more experience per hour than the other and also costs less or gives more profit, then there is no question which method is more efficient. However, if one method gives faster experience than the other but costs more or gives less profit, then the most efficient method depends on how much the player perceives his/her value of time to be. It is possible to calculate which method is more efficient for a player with a known value of time, or at what value of time the two methods are equally efficient.

Efficiency cannot take into account enjoyment of the game and therefore a method considered "most efficient" may not necessarily be the preferred method. However, for many players, it would be.

### Finding the better method for a known value of time

One way to compare two methods for training a skill is by using the equation:

where:

- E is the efficiency ratio, in coins per XP. A
*lower or negative value*indicates a more efficient method. - V is your value of time per hour. This comprises not only the profit per hour if you spent the time moneymaking, but may also include the value of experience. For example, if Graahk nature runes at 91+ Runecrafting is 900k profit per hour, someone with 91+ Runecrafting should value their time at least 900k per hour â€“ but may wish to add on some additional amount to take into consideration runecrafting experience gained.
- P is the positive profit per hour of the method being considered. If it costs money, P is negative.
- X is the experience per hour of the method being considered.

This equation primarily models methods that give experience in a single skill. Methods that give experience in multiple skills can only be used if only one type of experience is being considered - however, the experience in the other skill (ie the one not being modelled) would give the method an edge in value, compared to methods that only give experience in one skill. Thus the equation would not be as effective. The equation also cannot be used to compare training methods from different skills; it can only be used to compare methods to train the same skill.