Quantitative Research Design Sarah Sinks

Quantitative Research: Systematic scientific investigation of data and their relationships.

Overview of Qualitative research The objective of quantitative research is to develop and employ mathematical models, theories and hypotheses pertaining to natural phenomena. Measuring is key in quantitative research because it shows the relationship between data and observation.

Correlational Research To find if the data has an observable relationship that can be further specified in terms of magnitude and/or an increase or decrease.

Characteristics of Correlational Research Correlation indicates the strength and direction of a linear relationship between variables.

Correlation and Significance Is there a relationship between two variables/data? What is the direction of the relationship? What is the magnitude? These relationships may show any tendency for the variables to vary consistently. Pearson’s product moment coefficient correlation: -1.0 to +1.0

‘from what is done afterwards’ Ex post facto ‘from what is done afterwards’

Studies that investigate possible cause and effect relationships by observing an existing condition or state of affairs and searching back in time for plausible causal factors.

Characteristics of Ex Post Facto Researcher takes the effect/dependent variable and examines it retrospectively Establishes causes, relationships or associations and their meanings. Researcher has little to no control over independent variables. Flexible by nature.

When to use this? You can use this where more powerful experimental designs are not possible; when you are unable to select, control and manipulate the factors necessary to study cause and effect relationships directly, or when control variables except a single independent variable may be unrealistic and artificial.

Ex post facto advantages and disadvantages Show a correlation where more rigorous experimentation is not possible Exploratory tool Useful to avoid articiality in the research. Shows cause and effect relationships Disadvantages Lack of control for independent variable and randomizing subjects. Never certain if causative factor has been included or identified Relationship between two factors does not est. cause and effect. May be regarded as too flexible.

Experimental Research in which the investigator deliberately controls and manipulates the independent variable to observe the effect of that change on another the dependent variable.

How and when to use Experimental Research Most commonly used in Educational research. You vary the independent variable and look for the effect it has on the dependent variable.

How and When to use Quasi-experimental research Used when you have control over the “when and the whom of measurement”, but lack control over the “when and to whom of exposure.” Common in educational research.

How and when to use Single Case research Process of continuous assessment of some aspect of human behavior over a period of time. Involves “intervention effects”, that are replicated in the same subject(s) over time. Used in many fields including psychology, education and social work.

How and when to use Meta-analysis research Research to explore the effectiveness of classroom methods. Involves aggregating the results of other studies into a coherent account.

Useful Terms Correlation- Indicates the strength and direction of a linear relationship between two random variables. Ex post facto- from the Latin for "from something done afterward" Quasi- the prefix 'quasi' denotes methods that are "almost" or "socially approximate" Variable- a measurable factor, characteristic, or attribute of an individual or a system

References Research Methods in Education 5th Edition, Louis Cohen, Lawrence, Manion and Keith Morrison 2004, New York http://en.wikipedia.org/wiki/Main_Page, 4/10/2007