# Shared Flashcard Set

## Details

Political Science Methods
Basics of methodology: DV/IV, theory/hypothesis, etc
62
Political Studies
10/21/2012

Term
 Empirical
Definition
 : information acquired by means of observation or experimentation
Term
 Normative
Definition
 opinion
Term
 Unit of Analysis
Definition
 the type or levels of political actors to which the hypothesis is thought to apply
Term
 Theory
Definition
 a body of statements that systemize knowledge and explain phenomenon
Term
 Hypothesis
Definition
 derived from theory, makes a specific prediction that can be empirically verified. It predicts that 1+ causal factors will produce a single effect.
Term
 components of a hypothesis (4)
Definition
 Unit of analysis Independent variable Dependent variable Direction of influence
Term
Definition
 Give a value judgment Be immediately verifiable (e.g., be a fact)
Term
Definition
 Be an empirical statement Be testable Have an explicit comparison State a direction of influence State a unit of analysis Have clear concepts
Term
 Independent Variable
Definition
 explanatory/treatment/control
Term
 Dependent Variable
Definition
 outcome
Term
 External Validity
Definition
 the validity of generalized inferences in scientific studies, usually based on experiments as experimental validity—extent to which the results of a study can be generalized to other situations and to other people
Term
 Internal Validity
Definition
 the ability to show that variate of the independent variable actually causes the dependent variable to change
Term
 5 criterion for showing causality
Definition
 #1: temporal ordering: the IV must occur before the DV #2: correlation: two variables are correlated when changes in the variable occur together with changes in the other #3: causal mechanism: you have to be able to tell a plausible story that connects the IV to the DV (often includes an intervening variable” that gets us from IV to the DV #4: rule out confounds: we can say that X and Y are confounded when there is a third variable that influences both X and Y #5: correct unit of analysis: ecological fallacy: the use of data at an aggregate level of analysis to draw inferences about individuals
Term
 Intervening Variable
Definition
 : gets us from the IV to the DV
Term
 Confounding Variable:
Definition
 causes changes in the DV, is correlated w/the IV, and is “casually prior” to that independent variable—chronologically or logically, it comes first
Term
 Temporal Ordering)
Definition
 : the IV must occur before the DV
Term
 Random Assignment
Definition
 : split cases into 2+ groups of 30+ through a process that’s truly random—using a random # generator is key
Term
 Control Group
Definition
 : placebo group
Term
 Treatment Group
Definition
 : gets treated!
Term
 Experiment: (4 steps
Definition
 #1: random assignment #2: pretest: to check how the random assignment process worked, measure the value that the DV takes on for each case before any treatment has been applied. Each group should average about the same values of DV. #3: apply the treatment #4: post-test
Term
 Natural Experiment:
Definition
 nature assigns cases to control and treatment groups in some nearly random manner
Term
 Field Experiment
Definition
 : researcher assigns cases to control and treatment groups randomly in a real-world setting
Term
 Quasi-Experiment
Definition
 : scientists merely observe 2+ groups of cases that have been treated differently; may often be referred to as an “observational study”
Term
 Convergent Validity
Definition
 : refers to the degree to which two measures of constructs that theoretically should be related are related: established if two similar constructs correspond with one another Ex) participants rate how well they sleep and are also video recorded; convergent validity means that the two scores are similar
Term
 Divergent Validity
Definition
 : indicates that the results obtained by an instrument do not correlate to strongly with measurements of a similar but distinct trait Important because it is common to come up with an operational definition for a construct that actually measures more than one construct (e.g. trying to measure for anger and accidentally also measuring for depression) Ex) sleep quality and sleep quantity
Term
 Operational Definition
Definition
 : complete recipe for going out into the world and measuring a variable
Term
 Cross Sectional Research Design
Definition
 : make comparisons across cases (ex states)
Term
 Time Series Research Design
Definition
 : make comparisons over time
Term
 Measured Value
Definition
 : true value + bias (validity) + random error (reliability) The most worrisome measurement issues must be correlated with the independent variable in order to lead to false positives; most measurement problems will bias your research in the direction of not finding a significant result
Term
 Measurement Validity
Definition
 : degree of correspondence between measures
Term
 Measurement Reliability
Definition
 : the extent to which an experimental test or any measuring procedure yields the same results on repeated trials
Term
 History Threat
Definition
 : something that happens during the course of the experiment that externally threatens the test
Term
 Contamination Threat:
Definition
 control and experimental group interact
Term
 Regression to the Mean Threat:
Definition
 if a variable is extreme on its first measurement, it will tend to be closer to the average on a second measurement and—if it is extreme on a second measurement, I will tend to have been closer to the average on the first measurement
Term
 Hawthorne Effect:
Definition
 people act differently by dint of being tested
Term
 Maturation Threat:
Definition
 subjects grow and change
Term
 Random Sampling:
Definition
 one chosen by a method involving an unpredictable component
Term
 "Controlling" for:
Definition
 setting other things constant
Term
 Histogram:
Definition
 a graphical representation showing a visual impression of the distribution of data—it’s an estimate of the probability distribution of a continuous variable
Term
 Bar Chart
Definition
 : visual representation of chronological data
Term
 Box and Whiskers
Definition
 : bottom and top of the box are always the 25th and 75th percentile (the lower and upper quartiles) and the band near the middle of the box is the 50th percentile; the ends of the whiskers can represent several possible alternative values—upper and lower extremes
Term
 Density
Definition
 : function of both the bin-width and the proportion (proportion/bin-width)
Term
 Frequency
Definition
 : how often something occurs
Term
 Sample
Definition
 : subset of the population which is used to gain information about te whole population
Term
 Population:
Definition
 entire group of cases about which you want information
Term
 Statistic:
Definition
 number describing a sample; statistics vary from sample to sample
Term
 Parameter:
Definition
 number describing a population, usually a mystery
Term
 Nominal:
Definition
 you can put cases into a category, but can’t specify an order or relationship between the categories (ex. Religion: Catholic, Protestant, Mormon Jewish) Dummy variables: variables that only take on two values, usu coded as 0 and 1
Term
 Ordinal:
Definition
 you can put cases into different categories and order the categories (ex. Strength of religious belief) Differences between numbers don’t mean anything: values between numbers don’t correspond to actual value
Term
 Interval:
Definition
 not only can you order the categories of the variable, you can specify the difference (ex. Calendar years and temperature)
Term
 Ratio
Definition
 interval measure but 0= absence of the measured thing (ex. Income)
Term
 Mean
Definition
 : average
Term
 Median
Definition
 : 50th percentile (if you’re in-between, go for the average)
Term
 Mode:
Definition
 most commonly occurring number (if there’s two most-commonly occurring numbers, they’re both modes)
Term
 Range
Definition
 how spread out the data is (highest number – lowest number)
Term
 Interquartile Range:
Definition
 from your 25th percentile to your 75th percentile; cuts off outliers (find the median, find the medians of either side of the median, subtract the two from each other)
Term
 Standard Deviation:
Definition
 shows how much variation or dispersion exits from the average (low standard deviation indicates that the data points tend to be very close to the mean)
Term
 Measures of Central Tendency:
Definition
 any of a number of ways of specifying a central value—average of set measurements. A measure of central tendency is a measure that tells us where the middle of a bunch of data lies. The three most common measures of central tendency are the mean, median, and the mode.
Term
 Measures of Dispersion:
Definition
 describing the spread of the data or its variation around a central value--range
Term
 Skewed Right:
Definition
 hump w/ tail on the right; means that the mean is greater than the median, represents extreme values that are pulling the values to the right
Term
 Skewed Left:
Definition
 hump w/ tail on the left, means that the median is greater than the mean
Term
 Margin of Error:
Definition
 how the sample deviates from the population
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