Topic 3 Research Design: An Overview Flashcards
What is a Research Design
the overall strategy that you choose to integrate the different components of the study in a coherent and logical way
- plan for answering a research question using empirical data
Method-> design
Quantitative + Qualitative
Focus
Quan = specific beh that ben easily quantified (questionnaires)
Quali= people beh in natural settings and describing their world in their own words (discussions)
Objective
Quan= quantify data and generalise results from a sample to understand the population of interest -> track data over time
Qual= understanding underlying reasons or motivations -> provide insight into setting of a problem
HOW MUCH Sample and data collection FOR QUAN AND QUAL STUDIES
Quan = LArge and broad, statistically projectable
- standardised instruments, operation of variables
Qual = small and narrow, not statistically projectable
- adapted to the situation, variables not defined in advance
types of quantitative research
types of qualitive design
Quan
- experimental
-> true-experimental
— Iv manipulated
— random assignment
— Control group or multiple measure
-> quasi-experimental
— Iv manipulated
— NOT random assignment
— Control group or multiple measure
-> single-subject
— IV manipulated
- non-experimental
-> Analytical/correlational (w comparison)
-> Descriptive (w/out)
survey studies, naturalistic/ecology, meta-analysis study, case-study
qual
- ethnography, case study, historical, in-depth interview, document review
observational methods
objectives, methods, issues
naturalistic objectives, methods, issues (qualitative)
-> complete accurate picture of what happened in setting
-> keep detailed field of notes, write or dictate on a regular basis
-> subectivity, alteration of results if not concealed observation, time consuming
Systematic objectives, methods, issues (quantitative)
-> obs. of a specific beh in a setting, develop hypothesis
-> coding systems: decide which behaviors are of interest, choose a setting, observe and codify
-> equipment, reactivity, reliability
quan - Experimental -> true experiment
goal> psych to understand human beh - accurately describe causal underpinning - predict beh
-> cause-effect relationship
-> using predictive analytics
is the use of statistical algorithms to identify the likelihood of future outcomes based on data
-> having high internal validity
estabilish trustworthy v relationship (eliminate alt explanations)
quan - Experimental -> true experiment 2
Maximise independent variance
Minimize error
controlling external variable
-> large samples outcomes predicted by chance have a Normal (Gaussian) distribution (bell shaped curve)
mean = average outcome
other outcomes are distributed around the mean
-> outcomes gets smaller
variance
variance is the amount that scores vary around the mean score (SHOULD BE SIMILAR BETWEEN THE GROUPS)
= HOMOgeneity (sameness) of variance
= non-homogeneity of variance => if they are not similar, it might affect the validity of the outcome. Statistical significance is often based on how much the scores vary
How do we minimise error variance / controlling external variable?
- large group of participants
- suitable measuring instruments
- rigorous research planning
- balancing the design
- removal of outliers
- assumption of normality
controlling external variables - balancing the design
balanced designs have equal numbers of observation for all possible level combinations - compared to unbalanced
balance 30 - 30 - 30
unbalanced 30 - 28 - 30
controlling external variables - removal of outliers
def - data points that significantly differ from other observations. They can arise from data variability or measurement errors, potentially skewing results and leading to inaccurate conclusions. Identifying :
-> visualise :
Box Plots - Show the spread of data points to identify outliers.
Scatter Plots - Visualize relationships between variables to spot outliers.
-> statistical methods
Z-Scores - Calculate the z-score for each data point; values beyond ±3 are typically outliers.
Interquartile Range (IQR) - Calculate IQR (Q3 - Q1). Points below Q1 - 1.5IQR or above Q3 + 1.5IQR are considered outliers.
-> automated detection
Automated Detection - Use algorithms like DBSCAN to detect outliers based on data distribution.
Controlling external variable - Assumption of normality
When the data do not have a normal distribution. A possible way to fix this is to apply a statistical transformation. Transforming data is a method of changing the distribution by applying a mathematical function to each participant’s data value. -
like log transformation for a positively skewed to a normal distribution
exponential transformation for a negatively skewed residual to a normal distribution
DEFINING THE EXPERIEMENTAL METHOD
- cross-sectional studies
different group of people are tested at the same time and their results are compared. Quick to carry out, easily replicated to test the reliability of the findings - longitudinal studies
participants are studied over a long period of time -> track development, monitor changes over time - cohort studies
several groups are studied over a long period of time
example
exposed -> ->
time passes compare
not exposed -> ->
Within-subject
each participant takes part in all experimental conditions
between-subject
each participant takes part in one experimental condition