Board Thread:Wiki discussions and announcements/@comment-4881935-20140514222931/@comment-1330314-20140520043113

Feirund wrote: Cost-efficiency is an extremely speculative attempt at evaluating an item, one that will never go all the way - because, simply put, you cannot measure many particular details due to there being no relative common ground (as in, you can determine the relative value of a single ability point, but you cannot generalize a unique ability - the very terms are completely incompatible).

You make it look as if the people responsible for establishing the measures of gold value on this wiki plucked the values for each item out of thin air and called it a day. That's not how gold value works. It's actually based on pretty logical tenets:
 * Because in-game you're paying for stats, i.e. sinking X gold for Y points of whatever, each stat must be worth a certain amount of gold per point.
 * At the most basic level, you're going to be sinking a certain amount of gold to get a certain amount of a raw stat (i.e. 360 gold for 10 attack damage on a ). Since there are items out there that give a certain amount of one stat for some price in gold, we can use these basic components to establish the gold value of a stat, since that's how much you're going to be paying to get your gold's worth of a stat on a basic component.
 * From this you can find the gold value of most stats just by looking at their components. For others, you simply look at items in the next tier, take out the previous stat, and find the gold value for the new stat. In case of conflict, pick the least gold-efficient item, as this better reflects the fact that items tend to become more gold efficient the more expensive they become.
 * Under the assumption that the gold value of a stat never changes, you can therefore establish the gold value of complicated items with multiple different stats. Extrapolating even further, you can even state the gold value of an item under certain situations, based only on the gold value of the stats they're contributing at those precise moments.

To summarize, gold value isn't speculation, it's a precise and helpful tool in establishing how much gold's worth you're getting from your items at any given time. It also tends to be pretty accurate with regards to the item's effectiveness in general, bar moronic situations like building on : for example,  can reach a value of 13773 gold while its active is in effect on a full team. This sounds unreasonably high, but is an expression of the item's power at the time it is providing stats with the above value during the active's very short uptime. Although the precise value is not known to most players, people who have felt this item's active are somewhat aware of the amazing utility it provides, which is why the item is by far the most picked out of all three major support items. A quick look at the cost analysis of will tell you that it's massively gold efficient, even if you don't have any AD scalings and are manaless, in spite of the item offering stats only in small doses and being one of the most expensive items in the game. Information like this can influence decisions, and in a good way. Obviously, assuming that the effectiveness you'd get out of any item would be the same on all champions would be ridiculous, but that's not what gold value is meant to do.