Types if Flaws (Assumption Question)

evidence contradicts conclusion (uncommon)

blatantly draws a conclusion in conflict with what its evidence implies; e.g., “Management’s position in the negotiations is strong. You can see this from the numerous concessions they’ve made to labor.”

circular reasoning (uncommon)

draws a conclusion based on evidence that simply assumes the truth of the conclusion

part v. whole

draws a conclusion about a group based on evidence about individual members, or vice versa

equivocation (uncommon)

uses the same word or term inconsistently in the conclusion and evidence

unwarranted recommendation

concludes in a recommendation based on an assumption that the benefit cited in the evidence overrides all other possible disadvantages to the recommendation

unwarranted prediction

concludes from past or present facts that something will happen without addressing possible or likely changes that would alter the outcome

possible vs. certain

concludes that something can or should occur simply because it could occur

unrepresentative sample

draws a conclusion broader than the sample used for a study or survey can support

unwarranted assumption

builds a bridge between mismatched concepts with no evidence that they are logically related

overreach

draws a conclusion beyond the scope of the evidence

formal logic (syllogistic errors)

confuses the necessary condition in the evidence for the sufficient condition, or vice versa

slippery slope (rare)

concludes a final, extreme outcome based on an assumed chain of casual events

overlooked reverse causes

concludes that X causes Y when evidence leaves open the possibility that Y causes X (or that a third factor causes both X and Y)

overlooked alternative causes

concludes that there is a single, particular cause when the evidence leaves open one or more alternative cause(s)

correlation v. causation

concludes that there is a causal relationship when the evidence only estab lishes a correlation (could be mere coincidence)