Recorded Training: 10 common mistakes debaters make & how to avoid them

Summary

Brendon Chen presents ten common debating mistakes: five involving case construction and five involving responses to opponents. His central principle is that debating is a comparative game of persuasion. It is not enough to show that a proposal has benefits or that an opponent’s argument has weaknesses. Teams need to explain why their side is more likely, more significant, or better than the alternative.

Chen also recommends learning from judging. Watching other teams can make their mistakes easier to assess objectively—and help debaters avoid repeating them.

Case-construction mistakes

1. Splitting the comparison into “our world is good” and “their world is bad”

A debate compares a proposal with an alternative, such as the status quo or another policy. Organizing a case into separate sections on why each world is good or bad can obscure that comparison.

Instead, identify the main criteria the debate turns on, then compare the sides under each one. For example, ask which approach produces faster economic recovery and which does so with less debt. This helps judges see how each argument establishes a comparative advantage.

2. Giving many reasons for one premise while leaving other burdens unmet

An argument may offer several reasons that an outcome would be desirable but fail to establish that the proposed policy would actually cause it. For instance, showing that fewer guns would be beneficial does not, by itself, show that a ban would reduce access to guns.

To avoid this:

• Check whether your reasons are genuinely distinct.
• Ask whether they meet the argument’s necessary burdens, including the causal link between the policy and the claimed outcome.
• Consider the marginal value of each additional reason. Extra support for one premise may be less useful than establishing a missing premise elsewhere.

An argument’s overall strength is limited by its weakest link.

3. Failing to explain what is different about an impact

Many impacts are marginal rather than entirely new: a policy may increase an existing benefit rather than create one from scratch. If teams do not explain what their contribution changes, opponents can argue that the benefit already exists or would occur anyway.

Identify what is specific to the policy or motion—such as who pays a tax, how it is enforced, or how the funds are allocated—and explain why that difference matters.

4. Skipping the first premise: why people behave as they do

Before arguing about how a policy will change behaviour, examine why the behaviour exists in the first place. That diagnosis can shape the rest of the debate.

For example, whether countries accept loans willingly or under pressure affects how their interests should be understood. Likewise, whether children commit crimes because of material hardship or violent, antisocial behaviour affects whether prison is an appropriate response.

5. Copying arguments without adapting them to the motion

Reusing analysis from other debates is acceptable when it is relevant, but generic arguments need to be tailored. Check for:

• Contextual differences: The setting or population may add important considerations. A debate about sport in disadvantaged communities, for example, may require analysis of social protection, not just sport’s general health benefits.
• Different comparison burdens: Legalization compared with the status quo is not the same as legalization compared with decriminalization. Arguments must reflect the actual alternative.
• Specific wording and systems: Adjust claims to the details of the motion rather than relying on a “cookie-cutter” case.

Responsive-strategy mistakes

6. Treating “their argument is unproven” as proof that your side wins

Showing that an opponent’s policy may not work does not automatically prove that it is harmful or that your alternative is better.

After making a response, explain how it improves your comparative case. Also ask whether the same criticism could be applied to your own side; if so, provide stronger reasoning for your characterization.

7. Relying only on mitigation

Mitigation reduces the likelihood or significance of an opponent’s impact, but it does not necessarily establish an advantage for your side. A long list of small qualifications can also be difficult for judges to weigh, especially if both teams’ impacts have been heavily reduced.

Consider more decisive responses:

• Disprove a necessary link in the opponent’s argument.
• Flip the argument by showing that the opponent’s premise supports the opposite conclusion.
• Use mitigation when it is the only viable response, but explain clearly how much it reduces the impact’s likelihood or significance.

8. Counter-asserting a different characterization

Simply saying “people will behave this way” in response to an opponent’s “people will behave that way” may leave both claims equally plausible.

Explain why your characterization is more likely. Alternatively, assume the opponent’s characterization for the sake of argument and show why your side still wins on those terms. This avoids making the outcome depend entirely on a hard-to-resolve disagreement about what people will do.

9. Using symmetry without considering its effect on your own case

A symmetry response says that a harm or benefit would happen regardless of the policy. But if the opponent’s harm is symmetrical, your own benefit may be symmetrical too.

Use symmetry as part of a two-part response: neutralize the opponent’s impact, then establish a distinct advantage for your side in another area.

10. Critiquing an argument without rebutting it

Identifying a flaw—such as saying an argument lacks a mechanism—is not enough if the criticism is merely asserted.

Explain why the flaw matters: show why the argument is unlikely to be true, what necessary step fails, and what consequences follow. Responses need supporting reasoning and an explanation of their impact, just like substantive arguments do.

Speakers and sources featured

• Brendon Chen — presenter; the auto-generated subtitles render his name as “Brennan.”
• Audience members — unnamed participants contribute brief answers and ask a question; one participant is addressed as Ben.