Use of Data & Evidence

- If you are using statistics, make them easy to understand (e.g. 1 in 12 rather than 8.4% because many people have trouble figuring out relating to a multidigit number like 8.4%)

- May need to look at statistics over a year or country to make them sound bigger or over a day and per person to make them sound smaller. State your source for any evidence briefly but in such a way as to add credibility

- If a claim is surprising or not generally know, it is more likely to be believed if you give a source. This is essential for debates in the US, but is useful in most debates. Extraordinary claims require extraordinary evidence to back them up

- Make certain that they apply to the area under debate ,e.g. the same country, or that the facts are still relevant

- reputable Internet sites can be useful. Often claims are from unreliable ones. 

- Quotes from, or the opinions of, authorities in the area are good support

- It can be useful to use one of their examples against them, either by changing the situation slightly or carrying further or for longer, or showing that a different principle was involved

- Put a human face on the problem. Stories and anecdotes connect well with an audience, often more than statistics. The key is are they generalized or unusual, and you can use stats to prove or dispove this.

- give an  anecdote then show that it is of general application

- When looking at your opponent's arguments or evidence, see if any these issues that we mentioned above are possible weaknesses in their case

- More detail, background, and context can be crucial for attacking an argument based on statistics

• False positives and negatives. This can challenging to work out, but the math is clear. e.g. if a test has only a .1% chance of a false positive (so 100 out of every 100,000 will be false positives where the test is positive but you dont have the condition), but only 1 in 100,000 people have the illness, then a positive result is much more likely to be a false positive than an actual positive, since out of every 100,000 there will be 1 accurate positive and 100 false positives. This is a tricky notion for people to grasp, so if you are using it, explain it carefully.

• Percentage change vs absolute values e.g. something doubles the rate of cancersounds alarming, but is less crucial if the rate is incredibly low e.g if something doubles the rather of cancer but that means going from 1 in a billion to 2 in a billion, it is not actually alarming.

• Context - if the population is very low then per capita rates or percentages can change due to what is actually a small number more or less. Similarly if a rate reaches a historic low it will eventually go up sometimes by a large % but a small amount even if it is just a random change in rate, e.g. in a country the murder rate increased by 20% since last year, but if last year's rate was the lowest in history and the 20% increase was 1 more murder, there isnt a need to panic .

• Devil is in the details - sometimes more information about the situation can neutralize or even switch the arguments , e.g. discrimination on wages, etc. Family farms, inheritance tax,

• look at the numbers. provide other stats for perspective. are 80 deaths a huge number or a small one. If you are trying to make it look like a small number, compare it to a statistics that people see as rare such as deaths from lightning. You should still sound sympathetic though and not imply that you do not care about the 80 deaths.