Research Methods in Abnormal Psychology

Vocabulary flashcards covering epidemiology, observational and correlational designs, criteria for causality, and experimental methodologies in abnormal psychology.

Epidemiology

The study of the distribution of diseases, disorders, or health-related behaviors in a given population.

Incidence

The number of new cases of a disease or disorder that occur over a specified period of time, typically $1$ year.

Prevalence

The total number of active cases of a disorder present in a population at any given period of time.

Point Prevalence

The number of active cases of a disorder present in a population at a single, specific point in time.

$1\text{-Year}$ Prevalence

The total number of active cases of a disorder observed in a population at any time across a span of $1$ year.

Lifetime Prevalence

The total number of people in a given population who have experienced a disorder at any point throughout their entire lifespan.

Observational Designs (Correlational)

Research designs that involve no experimental manipulation of variables and focus on measuring the statistical relationship between two variables.

Pearson’s $r$

A statistical index ranging from $-1$ to $+1$ that quantifies the strength and direction of the linear relationship between two variables.

Positive Correlation

A relationship where two variables change in the same direction, such that an increase in one variable corresponds to an increase in the other (e.g., time studying and grades).

Negative Correlation

A relationship where two variables change in opposite directions, such that an increase in one variable corresponds to a decrease in the other (e.g., time partying and grades, or ambient temperature and clothing worn).

Spurious Correlation

A situation where two variables appear to be correlated, but the relationship is entirely caused by an unmeasured or unknown third variable.

Third Variable

An unmeasured or unconsidered factor responsible for the observed statistical association between two variables, such as antipsychotic medication explaining the correlation between schizophrenia and obesity.

Criteria for Causality

The three conditions necessary to prove a causal link: ($1$) a correlation must exist, ($2$) the cause must precede the effect in time, and ($3$) the relationship must be non-spurious.

Hypothesis

A testable and falsifiable prediction or idea about what will happen in a study.

Independent Variable

The variable that the researcher directly manipulates in an experiment (e.g., treatment condition versus a waitlist control group).

Dependent Variable

The measured outcome in an experiment that is observed to assess the effect of the manipulated independent variable (e.g., depressive symptoms).

Random Assignment

The procedure of assigning participants to experimental conditions by chance to ensure equal probability of assignment and minimize preexisting group differences.