Not an exhaustive list, but some of the ways to compare evidence and the reasons they are important.
1. Recency- certain uniqueness arguments, like the economy, can change rapidly. Having the most recent card on an issue is important if some event has occurred that will change forecasting or indicators.
Lets pause of a second and discuss the types of uniqueness evidence:
A. Snapshot- this is the world as it is right now. There ARE 60 votes for healthcare now is a snapshot.
B. Trend- how are things moving- in what direction. There WILL BE 60 votes for healthcare come vote time.
Now obviously you can have comparisons between Snapshot and Trend as well- and arguments about which to prefer. In general, dates affect both kinds of uniqueness, but snapshot in a larger way. The stock market may fluctuate from day to day, but those fluctuations do not necessarily deny that the TREND is going in a particular direction.
What does a complete argument using this look like? Unfortunately most people stop at “our card is newer and thus better”. This is a claim without a warrant. A complete argument would be something like “Their healthcare won’t pass evidence is prior to the death of Kennedy, his death has created a movement to get reform done, prefer our more recent evidence because it takes this pivotal event into account”.
2. Qualifications. There are basically 3 ways a piece of evidence can be “qualified”
A. It is written by an expert in the field- the field being what the card is talking about.
B. It can quote someone who would pass the test established in A. This is dicier- many cards quote someone qualified and then go on to make unqualified conclusions based on that quote.
C. It can site data-this is similar to B but the card is not necessarily “quoting”someone in the sense of having a sentence uttered by another person in the card. Instead it reports on data published by an individual or organization.
Both B and C are also prone to mis-reporting. Quotes can be taken out of context, data misreported or misused etc. So similarly to “primary” vs “secondary” sources, many scholars would say A is better than B or C. One thing debaters do frequently is to get a piece of evidence that is very qualified to make claim X, but then primarily use the piece of evidence to make claim Y, for which there is not a qualification. So qualifications arguments made by both sides should be scrutinized heavily.
The types of qualifications arguments:
A. Experts vs non experts- this is simple- your card comes from a staff writer, mine comes from a Nobel prize winning economist.
B. Biased vs unbiased- your evidence is written by someone with a financial or political agenda and is therefore suspect.
C. Reverse biased- my author has an incentive to say the opposite of what this card says, therefore that they is saying it proves it must be more true
D. Peer reviewed- similar to expertise but also separate- here an expert has been reviewed by other experts and had their conclusions (and more importantly their methods) found to be accurate.
3. Indicts and prodicts
These are arguments about whether a person or organization is qualified/unbiased in their assessments of things. These are obviously related to 2, I separate them out because they present their own set of arguments.
A. Ad Hom- X person is stupid or their organization sucks- the most common type of indict read. These are basically warrantless and I personally don’t think should be given much weight, particularly because if someone is taking a position on something they are going to generate a certain amount of hate mail.
B. structural- the school this person attended or the organization they work for structurally biases their claim. Examples of this would be “The Shock Doctrine” and its critique of Chicago school economics. These are generally better than A, but fall victim to the “this doesn’t indict the specific thing we have used this author to say” criticism.
C. Conduct- this is not really A or B, but close to both. Basically an author or institution has done something that would cast doubt on its objectivity- like accept oil money or some such thing. While accepting oil money does not in and of itself definitively prove that an organization is incapable of objective reporting on the issue of global warming, for most it does cast some doubt.
D. Methodology- probably the best kind of indict. This does not directly refute the claims made in a piece of evidence, but instead says that the way the author went about researching/testing those claims is flawed, and therefore their conclusions are also flawed. This is the most “academic” kind of indict because it requires someone to invest the time to dissect the claims of another.
E. Explicit refutation- this is the rarest form of indict and usually only occurs when someone writing evidence is sufficiently famous in their field to garner detractors. This would be something that says for example, “Zizek’s arguments about metaphoric condensation are wrong because…”
Prodicts generally follow the same logic
A. General props- this author is legit.
B. Structural props- they went to X or work for Y which have good reputations.
C. Conduct- they have won awards
D. Methodology- this study was sound
E. Specific praise- Their notion of XYZ is true and wonderful because….
Now if you read a prodict and the other side reads an indict, you want to similarly make comparisons about the class of arguments you are making, something along the lines off:
“Their indict is just an ad hom- it has no academic basis. Extend our prodict- this author has won numerous prizes for their economic writing. Prefer the prodict- it is very difficult to win awards like these, whereas we all know there are haters everywhere we go.”