Quantitative Research Design

Key features of quantitative research designs

Type of intervention?

Type of comparison?

How will confounding variables be controlled?

Will binding be used?

How often will data be collected?

When will variables be measures?

Where will study take place?

Experimental studies

Randomized control studies is the GOLD STANDARD (determines casual relationships)

Quasi-experimental

Similar to experimental/ lack either randomization or a control group (CONSIDERED WEAKER THAN EXPERIMENTAL)

Nonexperimental

No intervention completed- determines realtionships

Nonexperimental: Correlational research

Association between two variables

Nonexperimental: Descriptive research

Observe, describe and document (can not determine casual relationships between variables)

Retrospective (non-experimental)

(Post facto) Independent variable occurred in the past

Cross-sectional design (non-experimental)

Collect data about the independent variable and dependent variable at the same time

Repeated measures

Data collected at multi points in short period of time (provides baseline for each subject)

longitudinal design (experimental/ non-experimental)

Data collected from subjects at multi points in long period of time (provides info on relationship over time)

Control

Ability to manipulate, regulate or stat control for factors that can influence the dependent variable

Extraneous variable

Influence and distort the relationship between independent and dependent variables

Bias

Systematic error in selection of participants, measures of varibales or analysis of data

Randomization

Random sampling of partcipants or random assignment to experimental or control group

Statistical conclusion validity

Confidence that statistical analysis reflects the true relationship between the independent and dependent variable

Internal validity

Do we believe results of this study? is there an error in the design? are there problems with the sample?

External variables

Can we apply the findings to others in the population who are like the subjects in the study? Was the content too unique to the sample?

Construct validity

Concerned with whether instruments are really measuring the theoretical framework

temporal ambiguity

What is the timing of the variables? which came first

selection bias

findings are result of differences in participants, rather than the effect of the independent. Assuring sample is respresentive of population

History

Happens when event happens inside or outside the context of the study that effects the dependent variable

Maturation

Happens when developmental physical, pyschosocial, spiritual processes that operate in individuals as a function of time and are external to the investigation. (prevented by shorted time for study and using control group)

Mortality

Happens when loss of partipcants during study (reduce pt burden and give incentives)

Hawthrone

Act of participating in the study changes that behavior of the partipants