sociologymethods 120903105424-phpapp02

{Research Methods

Quantitative, qualitative and critical thinking

Where to begin?

Hypothesis: a proposed explanation to a phenomenon

A hypothesis is an assumption made from your own knowledge or common sense.

 Correlation refers to a relationship between two (or more) variables in which they change together.

A positive correlation means that as one variable increases(e.g., ice cream consumption) the other variable also increases (e.g., crime). A negative correlation is just the opposite; as one variable increases (e.g., socioeconomic status), the other variable decreases (e.g., infant mortality rates).

What is correlation?

Yes…there is a correlation.

Causation refers to a relationship between two (or more) variables where one variable causes the other. In order for a variable to cause another, it must meet the following three criteria:1. the variables must be correlated2. one variable must precede the other variable in time3. it must be shown that a different (third) variable is not

causing the change in the two variables of interest (a.k.a., spurious correlation)

What is causality?

Correlation is not causation.

Does it meet all three criteria?

Spurious Correlation

Independent Variables

1. These variables are ones that are more or less controlled.

2. Scientists manipulate these variables as they see fit.

3. They still vary, but the variation is relatively known or taken into account.

4. Often there are many in a given study.

Dependent Variables

1. Dependent variables are not controlled or manipulated in any way, but instead are simply measured or registered.

2. These vary in relation to the independent variables, and while results can be predicted, the data is always measured.

3. There can be any number of dependent variables, but usually there is one to isolate reason for variation.

Independent

(input)

1. Intentionally manipulated

2. Controlled3. Vary at known rate4. Cause

1. Intentionally left alone

2. Measured3. Vary at unknown

rate4. Effect

For example:

•If a scientist conducts an experiment to test the theory that a vitamin could extend a person’s life-expectancy, then the independent variable is the amount of vitamin that is given to the subjects within the experiment. This is controlled by the experimenting scientist. 

•The dependent variable, or the variable being affected by the independent variable in this case, is life span. 

Dependent (output)

Example: What affects a student’s arrival to class?

Variables:Type of School

Liberals Arts v. UniversityType of Student

Athlete? Gender? GPA?Time

Bedtime, Waking, ArrivalMode of Transportation

http://www.wired.com/medtech/drugs/magazine/17-09/ff_placebo_effect?currentPage=all

Researchers beware!

Reliability and Validityhttp://www.wadsworth.com/psychology_d/special_features/ext/workshops/reliability3.html

Reliability and Validityhttp://www.wadsworth.com/psychology_d/special_features/ext/workshops/reliability3.html

Reliability and Validity

Ethics

“do no harm,” informed consent, voluntary participation, and protected populations.

Science, junk science, pseudo-science and non-science.

http://www.youtube.com/watch?v=8T_jwq9ph8k

Keeping it real.http://www.ted.com/talks/ben_goldacre_battling_bad_science.html

RESEARCH