EPI 390Exam # 1 Study Guide Lectures: 1 - 9Lecture 1 Characteristics of Inductive and Deductive Reasoning/Logica. Inductive (aka instinctive) reasoning – A conclusion is drawn from specific instances/examplesi. Premises of the conclusion are based off of facts and observations, though it is possible for facts to be correct while conclusion is false.ii. Inductive reasoning is mostly descriptive. It involves stating ideas and generating hypotheses or discovering relationships, only as the very beginning. 1. Very simple. iii. Example: There are more females than males in this course. You can count the number of females v. males, but the result is merely descriptive. Need to continue on to ‘why?’, ‘what does it mean for the population?’.b. Deductive (aka ingenious) Reasoning – A conclusion is drawn from general principles or premises.i. The premise is a previously made statement from which another conclusion is inferred.ii. Conclusions from deductive reasoning are certain, unlike the uncertainty in inductive reasoning, provided the premises are true.Hypothesis generation vs. Hypothesis testingI. Inductive reasoning is typically for hypothesis generation; Deductive reasoning is for testing hypotheses.II. Generation is from observations and resulting questions; testing uses the scientific method (the hypothesis must be refutable and compatible with current evidence)Association vs. Causality; give examplesa. Defining Causalitya. Temporal Relation – Cause must precede effect (this can be difficult to determine in some cases)i. Just because one event happens first, doesn’t mean that it was the cause of the effect (post hoc conclusions)ii. i.e. Disease caused by infected cantaloupe b. Plausibility – the conclusion coincides with existing knowledge/evidencei. A lack of plausibility may simply be due to a lack of knowledge. You can’t know what you don’t know.ii. i.e. Obesity’s connection to: depression, bone health, heart health, etc.c. Consistency – Multiple studies give the same resulti. If 100 other tests get Z and you get X, you might be on to something new, but chances are you: didn’t have right variables, made mistake in stats, etc.ii. When comparing to previous studies, emphasis should be placed on studies with the most sound design.iii. i.e. Tobacco smoking and lung cancerd. Strength – a logical association with cause and effect. i. Looks at relative riskii. i.e. Smoking and lung cancer, again; what is the risk ratio of smokers/non-smokers of getting lung cancer (about 10)e. Dose-Response Relationship – Varying the amount of exposure from the event results in changing magnitudes of the effect.i. i.e. pharmaceuticals: depression medicine and symptom control; aspirin for pain relief vs. gastrointestinal bleeding1. When the dose increases or decreases, does the effect of the medication change? (side effects, symptom control)f. Reversibility – Removal of the possible cause results in a reduction of disease risk.Errors and Biases (Bogus Therapies)a. People tend to support their current believes and (consciously or not) select evidence that supports those while ignoring or discrediting evidence that refutes it.b. Time relationship can sometimes be confusing and hard to discern (see “confounding”, Lecture 4)c. The Placebo Effect – patients and consumers expect a certain result, so they will either convince themselves it occurred or associate the result (falsely) with the exposure event.What is a contingency table used for? Contingency tables show the outcomes for exposure (you were exposed, you weren’t) x outcomes for disease (you have it, you don’t)Be able to calculate: calculations are done using the chi-square statistics. Σ[(E-O)2/E], where E = the expected values and O = the observed values.Lecture 2 Cognitive thinking problems (6 of them)a. Confirmation bias – people are (subconsciously) driven to confirm their beliefs oropinions; they are more prone to remember supportive evidence and discredit orignore contradictory evidenceb. Fallibility of Human Memory – memories are easily lost or confused; people can also generate false memories of events that never occurred.a. Present beliefs or opinions can alter past memories.c. Stories over Statistics – Humans relate more to anecdotal evidence than numerical/statistical evidence, though this is prone to flaws like leaving out information and is biased.d. Observation vs. Reality – Humans perceive the world based on what they expect to see, not what is actually in the external world.a. Perceptual blindness is often used to discredit eyewitness testimonye. Oversimplifications – The amount of information needed for decision-making is overwhelming, so humans tend to simplify it to make it manageable but important facts are lost that way. f. Chance and Coincidence – Humans try to find causes for and explain chance events, even if there are no underlying cause-and-effect relationships.Correlation does not imply causality1. Two variables may seem to be connected, but that does not mean that one causes the other.1. False association can occur, i.e. through the above problems in cognitive thinking, confounding, etc.2. Coincidences do occurOccam’s Razora. “Don’t multiply the agents in a theory beyond what’s necessary” – William of Ockham,medieval theologian and logician.i. Aka with 2 competing theories, the simplest theory is more likely the correct one.Lecture 3Central Axiom of EPI and corollaries1. Disease does not spread randomly – epidemiology is about determining differences in the effected and non-effected; if disease spread randomly, it wouldbe impossible to find a cause. 1. Measure patterns in disease along axes of time, space, individual characteristics, and community characteristics.2. Variations in frequency of disease follow variations in intensity of exposure or to variations in susceptibility of the individual.In society, eyewitness/individual observations are the ‘gold’ standard1. The brain typically only sees what it expects to see1. i.e. In testing eye witnesses, they watch a video of teams passing a ball and are told to count the number of passes. They fail to see the gorilla pass in the background.2. Memories can be easily confused or created; the mind does not work like a recorder thatcan be rewound and replayed.3. Refer to Cognitive Thinking Problems (Lecture 2)What is a good working definition of epidemiology?1. Epidemiology – the study of distribution