Refutation is one of the skills in debate that can be conceptualized in many different ways. Your level of experience, conceptualization of a round, or style of refutation can all affect how you think about refutation. 

Many debaters use direct, global, and caseline clash as their initial way of understanding clash, while more experienced debaters use assumptions, or comparative as tactics in refutation. Another way to sort refutation is by using FETCH. 

FETCH is an acronym used in refutation to group refutation by the issue targeted in a specific line of refutation.

Facts

An opponent is misleading, or is wrong about a particular fact. This is a very common kind of refutation for beginner debaters because it is easy to see something incorrect when you have a statistic that counters theirs. This form of clash is typically ineffective. Arguing facts (unless the person is incorrect about something massive) is not impactful because the ideas supporting the argument have not been dealt with. 

Extension

You prove how the logical extension of your opponent’s argument is harmful, contradictory, or unrealistic. When done improperly, this form of clash can quickly become a slippery slope. Instead of thinking of the worst case scenario, try to find the realistic outcomes that are harmful. 

Tieback

The “so what” of your opponents case is logically inconsistent, false, and/or exaggerated. This is similar to global clash for those who are familiar to it. This form of clash is effective because it is refuting an entire argument at its impact. This kind of clash often requires multiple lines of refutation in order to effectively decimate the material. 

Contradiction

Your opponent’s case is not consistent. This could happen in several ways: the model and the argumentation are arguing for two different things, there is a contradiction between the two speeches, or two arguments contradict one another. The strongest format for this form of refutation is demonstrate where the contradiction is, prove why it’s harmful to their case, and then attack both lines of analysis anyways. This is a very successful attack because it simultaneously shows your opponent's weakness, and your strengths to the judges.

Harms

Your opponent’s case has a series of harms attached to it. This can be an unintended consequence, a large impact to a specific group, or it fails to solve the problem causing more harms. 

When refuting your opponent’s material, try using multiple pieces of FETCH in combination with assumptions, comparative, and your clash tree to organize your material into multiple responses per piece of refutation.