Indexing

Indexing is a common extraction method used in hunt puzzles. It involves using particular numbers to select the Nth letter of a given string of letters. It is likely the most common extraction method across all puzzle hunts currently in existence, due to its versatility and ease of accessibility, especially to new solvers.

Puzzle Application
At a basic level, indexing is very simple. Numbers can be paired with words or phrases in order to extract individual letters from each. For example, if a certain index is 6, then one would count 6 letters into the word/phrase/string and write down that 6th letter. Shopping List: 2 Bananas, 12 Hamburger Buns, 5 Radishes, 1 Watermelon, 4 Live Chickens, 3 Parsnips BANANAS (2), HAMBURGER BUNS (12), RADISHES (5), WATERMELON (1), LIVE CHICKENS (4), PARSNIPS (3) --> ANSWER

These numbers can be pre-paired with the strings as seen above, or they can be presented at the outset of the puzzle and paired up through the course of solving. A common example of this is two sets of clues, with one having indexes attached to them and the other not, resulting in pairing up clues and indexing into the half that didn't start with an index. Indexes may even have to be wholly determined through additional steps, providing an additional level of obscurity to the indexing revelation. One way to do this is by having answers associated with particular numbers, and being indexed into by their appropriate number. SNIVY TYPHLOSION RILLABOOM IVYSAUR FROGADIER Each pokemon gets indexed by its local pokedex number: SNIVY (1), TYPHLOSION (6), RILLABOOM (3), IVYSAUR (2), FROGADIER (8) --> SOLVE

There's also what has been called an "implied index", which is when a consistent index or series of indexes is applied to a set of information without ever being explicitly written down. This includes initialization (index of 1), diagonalization (increasing index of 1, 2, 3, etc.), and (debatably) centralization/terminalization. The latter two are debatable due to having the implied index change depending on the length of the answers in question, which makes it harder to "imply" via consistency.

Strategy
The action of indexing requires very little strategic thought. Two elements of indexing, however, have the tendency to make problems for solvers.

Is It An Index?
Whether or not a particular number or set of numbers found in a puzzle is actually meant to be used as an index can be a difficult question to answer, particularly if there are a lot of different sets of numbers being thrown around.

What Gets Indexed?
When a puzzle provides a lot of streams of information and expects solvers to index into a specific subset of that information, it's very easy to get confused. A good example of this is music identification puzzles, in which each track has a title artist, and track that have the possibility of being used.