1. Demonstrate understanding of concepts Flashcards
Confirmation bias:
tendency to give more weight to evidence that confirms our beliefs than to evidence that challenges them
Deductive reasoning:
Deduction begins with abstract theory and assumptions Economics relies heavily on deduction. Useful because does not require collecting observations like inductive reasoning does fast cheap BUT… just because logically consistent does not make the conclusion true.
Induction:
- We use deduction to derive (state) a TESTABLE hypothesis 2. We use induction, to test that hypothesis of what we expect to observe against empirical observations of what actually occurred. begins with observations about the world.
Bias against negative results:
There is nothing wrong, defective or unimportant about a study that fails to reject H0 Such studies are just as important as those supporting an effect
or a causal relationship. (Don’t say it ‘didn’t work.’)
E.g. Studies showing that a treatment or drug is ineffective fail to reject H0. There is unfortunately systematic bias against negative results Studies that get a negative result (uphold H0) tend not to get published and tend to be ignored by the public and policymakers e.g. Homeopathy is proven to be ineffective e.g. Trade liberalization does not cause lax environmental regulations
Independent and dependent variables:
The DV (Dependent Variable) measures the outcome, whatever is being caused. (We only look at one DV at a time.) aka “Y”. An IV (Independent Variable) measures one factor which is a possible cause. aka “X”. A single DV can and often will have many IVs. We test hypotheses to see which possible causes appear to be real causes and which are not.
Falsifiability/unfalsifiability
What makes something unfalsifiable: If there is no possible observation which could be inconsistent the proposition/hypothesis. If you can’t generate a prediction about what we expect to observe in any particular instance. Unfalsifiable = not scientific. Example: Whether the strike is put down by the government or workers win their demands, either outcome is consistent with the statement So hypothesis cannot be disconfirmed Also, can’t make a prediction about outcome of any specific strike. A falsifiable hypothesis requires separate, independent measures of the IV and DV E.g. explanations for sports victories
“The Giants just wanted it more.” How do we know they wanted it more? Because they won… This measures the DV based on the IV.
Internal validity:
Refers to the causal link between independent variables (which, for example, describe the participants or features of the service they receive) and dependent variables (particularly the outcomes of the program). Internal validity is concerned with whether the program is the agent responsible for observed effects, rather than external conditions, artifacts of the methodology, or extraneous factors. It indicates whether the relationship between program inputs and observed outcomes is causal. High internal validity when we can isolate the treatment that caused the outcome. If our design lacks internal validity, then NO • Threats to inference = Threats to internal validity
External validity (generalizability):
Concerned with whether the findings of one evaluation can be generalized to apply to other programs of similar type. If this one AIDS prevention program is successful, can we generalize this to other similar kinds of AIDS prevention programs? How far can we generalize the findings? To which class of AIDS prevention programs will they apply?
Problems with research question:
- Variation is required in both the IV and DV
- History doesn’t vary and if you introduce a counterfactual then it’s speculative
- Unmeasurable or hard to operationalize, like “power”
- Things that are hard to observe like “motives” and “norms”
- Telegolical – or will assume that the future will behave like the past
- Functionalist – Attributes personal needs/intentions to abstract constructs like society or the world Functionalist theory in IR – countries succeeded in cooperating because they needed to solve a problem
- Mismatch of units of analysis
Counterfactuals:
A counterfactual explanation describes a causal situation in the form: “If X had not occurred, Y would not have occurred.” Counterfactuals are not empirical, unless you have comparable cases for which the event did NOT occur - We can’t collect empirical evidence about a state of the world that did not happen, especially without comparable cases where the other outcome occurred. The hypothesis must be falsifiable, meaning others should be able to do the same test with the same methods and achieve the same results so that the hypothesis doesn’t rely on our opinions but the methods we employ
Random selection/sampling versus purposive sampling:
A purposive sample is where a researcher selects a sample based on their knowledge about the study (non-representative) and population. The participants are chosen based on the purpose of the sample, hence the name. Random sampling is a part of the sampling technique in which each sample has an equal probability of being chosen. A sample chosen randomly is meant to be an unbiased representation of the total population. … An unbiased random sample is important for drawing conclusions.
Randomization (random assignment to treatment and control groups):
In experimental research, random assignment is a way of placing participants from your sample into different treatment groups using randomization. With simple random assignment, every member of the sample has a known or equal chance of being placed in a control group or an experimental group. It prevents the selection bias and insures against the accidental bias. It produces the comparable groups and eliminates the source of bias in treatment assignments. The main purpose of random assignment of treatments, or of the order of treatments, is to even out confounding variables across treatments. By doing this, a cause-and effect conclusion can be inferred that would not be possible in an observational study. With randomization to treatments, the range of values for confounding variables should be similar for each of the treatment groups
The types of variables (e.g. nominal):
Nominal aka categorical for classification e.g. gender, countries, war/not war, yes/no on referendum. Frequency of cases, descriptive categories cannot rank or order values of the variable, so cannot assign a numeric value Common in IR.
Ordinal ranking, not distance no units e.g. social class – lower class, middle and upper e.g. Levels of education (not years) e.g. 1st, 2nd, 3rd in a race. Unlike nominal, can rank but cannot attribute a precise measure or number - e.g. high school, college, grad school - can’t put a linear scale or graph can’t express as a number because no units.
Ratio e.g. income, battlefield deaths, most economic data. continuous can express as a number can plot on a graph - can compare ratios, so can say “twice as much income” or “20% fewer casualties.”
Null hyotheses for testing:
We start by identifying a null hypothesis H0 that there is no causal relationship between the IV and DV. Establishing a relationship between variables proceeds by rejecting H0 - Only if we can reject the null hypo, can we find support for our alternative hypothesis (if it goes in the same direction as the data). The null hypothesis H0 - i.e. There’s no relationship between the variables. - i.e. IV has no effect on the DV Then we see if the data justify rejecting H0 or failing to reject H0. If we reject H0, there is a correlation (or association) between the variables. If we fail to reject H0, there is no correlation.
If we reject the null hypothesis, then, if our initial hypothesis goes in the same direction as the data, we can say the hypothesis is “consistent with the data” “supported by the evidence” “confirmed, not disconfirmed, by the results”
If we reject the null hypothesis, but our initial hypothesis goes in the opposite direction to the data, we can say we it is “inconsistent with the data” “not supported by the evidence” “disconfirmed by the results” Still a relationship, but opposite of what we expected initially.
Double barrelled hypothesis:
A hypothesis with two IVs is double barreled hypothesis That makes it impossible to know which IV caused any observed change in the DV, so basically useless. A confusing and poorly designed hypothesis with two independent variables in which it is unclear whether one or the other variable or both in combination produce an Skipping breakfast and drinking alcohol are associated with weight gain If observe weight gain, don’t know which factor caused it. Skipping breakfast? Alcohol? Only both together? Hence, useless as hypothesis test.