Exam II Study Cards Flashcards
Selection of Design
Consider feasibility of conducting study
Intervention Fidelity
Constant data collection
Experimental Design Features
Randomization
Control Group
Manipulation
Advantages: most appropriate for testing CAUSE AND EFFECT RELATIONSHIPS
Disadvantages: costly and difficulty in field
Experimental Design
For testing Cause and Effect relationships
Positivism
Real Natural Truth by observation Context minimized Neutral observer Experimental
Constructivism
Subjective Multiple realities Culture and environment Context emphasized Active participant w/ dialogue
Hawthorne Effect
Trial participants act differently to get attention
or please researcher
Quasi-Experimental Design
MANIPULATION OF A VARIABLE
- not random
Layouts:
- Non-equivalent (foam vs soap)
- After only non-equiv (no baseline data)
- one-group (pre/posttest; nurse residencies)
- Time series (some baselines, interventions applied and info gathered afterward)
Advantages: practical and feasible
Disadvantages: unable to make clear cause/effect statements; may not be able to randomize
Non-Experimental Design
No independent variable b/c already occurred
(smoker already smokes)
- concepts of control still observed w/in a cohort
Advantages: IMPORTANT when randomization, control, and manipulation are not appropriate or possible
Survey Studies (CDE)
Comparative
Descriptive
Exploratory
Correlational Studies
Relationships between variables
but does not determine cause and effect
Solomon-Four-Group Design
Tests AGAINST the THREAT of INTERNAL
VALIDITY of INSTRUMENTATION
Extraneous Variables
AKA Intervening/Mediating
Interfere w/ operations of variables being studied
Control w/:
homogenous sample; consistent data collection; training and supervision; manipulation of IV; randomization
Threats to Internal Validity
History; Maturation; Testing; Instrumentation;
Mortality; Selection Bias
History
Historical events that skew results
Maturation
Respondents change as time passes;
external to investigation
Testing
Repeated testing influences responses in the
future
Instrumentation
Measurements affected by instrument
calibration
Mortality
Loss of subjects from pre to posttest
Selection Bias
Respondents change own mind about
participating
External Validity
Questions conditions of findings
Internal Validity
Asks if IV caused or resulted in change in DV
“Truth Value”
Rules out threats as rival explanations of relationships between variables
Consider BEFORE PLANNING A STUDY to not negate results
Population
Well-defined set
Sample
Subset of units from a population
Accessible Population
Group of people available to make a sample
Exclusion Criteria
Restrict population to HOMOGENEOUS group
of subjects
Inclusion and Exclusion Criteria
Establish control for extraneous variability or bias that would limit the strength of evidence contributed by the sampling plan.
Careful establishment of criteria INCREASE PRECISION of the study and STRENGTH of EVIDENCE, contributing to ACCURACY and GENERALIZATION of the findings
REPRESENTATIVENESS
Key characteristics CLOSELY
APPROXIMATE those of the population;
foremost criterion in appraising a sample.
Who is CONVENIENCE SAMPLING
Any subject available that meets criteria and
will participate
Advantages: easy to draw
Disadvantages: HIGHEST
RISK OF BIAS b/c samples may volunteer based off of interest in study
QUOTA SAMPLING
-Fill spots with proportionate strata
represented (40/40/20)
-Oversampling to satisfy survey size
-BIGGER SAMPLE MORE REFLECTIVE OF TRUTH
-RECRUITMENT and ENROLLMENT.
-Representativeness INCREASED b/c prob of over/underrepresentation addressed.
-Characteristics of population selected according to researcher’s judgment and Lit review
PURPOSIVE SAMPLING (QUAL)
- MORE heterogeneous the population, -GREATER RISK of bias introduced
- Sample HANDPICKED so limited ability to generalize
PROBABILITY (RANDOM SELECTION)
Take the Simple and STRAight way to not get in a Cluster
- SIMPLE, STRATIFIED, AND CLUSTER
- AVOIDS BIAS but more time consuming
- Each subject has an EQUAL CHANCE OF BEING CHOSEN
- CLOSELY ASSOCIATED W/ EXPERIMENTAL AND QUASI
- STRONGEST TYPE OF SAMPLING
- Different then RANDOM ASSIGNMENT*
RANDOM ASSIGNMENT
Subjects ASSIGNED to experimental or control group on a RANDOM BASIS
SIMPLE RANDOM SAMPLING
- CAREFULLY CONTROLLED
- Researcher DEFINES the POPULATION, LISTS the UNITS of the pop (SAMPLING FRAME), and SELECTS a sample of units (SUBSET) from which the sample will be chosen
- LABORIOUS, TIME CONSUMING, INEFFICIENT
- CAUTION w/ reporting generalized findings, esp if pop difficult to list completely
- LOW BIAS
- REPRESENTATIVENESS MAXIMIZED but no guarantee
- Differences function of CHANCE
- Probability of non-representativeness DECREASES with INCREASED SAMPLE SIZE
STRATIFIED RANDOM SAMPLING
-Population DIVIDED into HOMOGENOUS
SUBGROUPS
-Elements from ea subset RANDOMLY SELECTED on basis of PROPORTION to the population
-Goal –> ACHIEVE GREATER DEGREE OF REPRESENTATIVENESS
-Question APPROPRIATENESS to problem under investigation
-TIME CONSUMING and DIFFICULT to OBTAIN POPULATION LIST W/ COMPLETE CRITICAL VARIABLE INFO
-CHALLENGE OF ENROLLING PROPORTIONAL STRATA AND TIME/$ INVOLVED FOR LARGE SCALE STUDY
-ENHANCED REPRESENTATIVENESS
-VALID BASIS FOR MAKING COMPARISONS AMONG SUBSETS IF INFO ON CRITICAL VARIABLES AVAILABLE
-OVERSAMPLE DISPROPORTIONATE STRATUM TO ADJUST FOR UNDERREPRESENTATION
SYSTEMATIC/Constant Error
Data collected in a consistent manner
Cluster/Multistage Sampling
Successive, RANDOM sampling of units/
clusters that PROGRESS from LARGE to SMALL and meet eligibility criteria
- 1st stage is Large
- 2nd stage is small
- 3rd stage is smaller
Advantage: more economical; less time consuming than simple or stratified
Disadvantage: more sampling errors and complexity of handling data; less representative
SAMPLING
Selecting representative units of a population
for study in a research investigation.
PURPOSE: to increase the efficacy of a research study
Convenience
Using the most readily accessible persons or
objects as subjects in a study
Advantages: easy to obtain subjects and appropriate
Disadvantages: risk of bias GREATER THAN any other type b/c volunteers can feel strongly about the issue being studied and favor certain outcomes; MOST COMMON BUT WEAKEST, so use CAUTION w/ data; make sure to obtain sufficient # of subjects who meet same criteria
Networking/Snowballing
Used to locate samples that are difficult to find
via social networks and friends to get in touch
with others
Purposive Sampling
Researcher’s knowledge of the population and it’s elements used to handpick cases to be included, especially if typical
- used when highly unusual group being studied to precisely describe sample characteristics to provide an accurate pic for the reader
- studies differential effect of risk factors in a specific pop longitudinally
Advantages: increasingly common; assumes errors of judgment in over/underrepresenting elements of the population in the sample will balance out
Disadvantages: no objective method for determining validity of assumption; the MORE HETEROGENEOUS the POPULATION, the GREATER the chance of BIAS being INTRODUCED in the selection; CONSCIOUS BIAS a CONSTANT DANGER, so regard findings w/ CAUTION; GENERALIZABILITY LIMITED
POWER ANALYSIS
Used to DETERMINE SAMPLE SIZE and FIND SIGNIFICANCE of a QUALITATIVE STUDY
Sample Size Implications
- BIGGER sample size more reflective of
TRUTH - Smaller size has less accurate results
- Non-Probability have lack of randomization and are less generalizable, producing less representative samples
NON-PROBABILITY (the Con Quoted for a Purpose)
NON-Random
- CONVENIENCE, QUOTA, AND
PURPOSIVE
-Non-random choosing methods - Easy to obtain sample; higher bias; and less representativeness
Random SELECTION/Probability (Sampling)
-Process of selecting a portion/subset of the designated population to represent the entire population
-Each element of the population has an
EQUAL and INDEPENDENT chance of being
included
-GREATER confidence of representative rather then biased
-more closely reflects characteristics of the population of interest
-Purpose: incr efficacy of research study
Random ASSIGNMENT (Randomization)
Distribution of subjects (indv or groups) to either experimental or control group on random basis, giving an equal chance of being assigned to any group
-req’d for a study to be considered a true experimental design
- reduces systematic/selection bias and minimizes variance
- assumes any imp intervening variables will be equally distributed between the groups
-
Triangulation/Crystallization
combing methods, theories, data sources, or investigators to converge of a single construct
- incr’s strength and consistency of evidence
- uses both qual and quant
Bracketing in Phenomenological (Lived experience) Research
Identify and set aside personal biases BEFORE interview to foster and open mind
Characteristics of a well-written study
ID the Phenomenon Structure the study gather the data analyze the data describe the findings
Credibility in Qualitative Research (tests rigor)
Truth of findings as judged by participants and others w/in the discipline
- do participants recognize the experience as their own?
- has adequate time been allowed to fully understand the phenomenon?
Auditability in Qualitative Research (tests rigor)
Accountability as judged by the adequacy of info leading the reader from the research question and raw data through various steps of analysis to the interpretation of findings
- can the reader follow the researchers thinking?
- Does the researcher document the research process?
Fittingness in Qualitative Research (tests rigor)
faithfulness to everyday reality of the participants, described in enough detail to that others in the discipline can eval importance for their own practice, research, and theory development
- findings applicable outside study situation?
- results meaningful to individuals not involved?
- analysis strategy compatible w/ study purpose?
Confirmablity = what
Creditibility + Auditability + Fittingness
- findings that reflect implementation of all three standards
Trustworthiness
RIGOR of goodness of data
EMIC View in Ethnography
MEMBERS/Insiders View
ETIC View in Ethnography
OUTSIDERS view
Data Characteristics
info that is systematically collected in teh course of a study
Data Collection Characteristics
both objective and systematic
- provide operational definitions of the relevant variables
- Collection and Analysis occur SIMULTANEOUSLY
Types of Data Collection
Self-Report
Observational
Physiological
Existing
Self-Report Data Collection
interviews, questionnaires, paper-pencil
Observational Data Collection
used when variables of interest deal w/ events or behaviors
- req’s preplanning, systematic recording, controlling the observations, and providing a relationship to scientific theory
- best suited for probs that are difficult to view as part of a whole
Advantages: flexibility to measure many types of situations; allow for depth and breadth of info to be collected
Disadvantages: distorted data as a result of observer’s presence; biased observation by observer
Physiological Data Collection
Physical, chemical, microbiological, or anatomical status; objective, precise and sensitive
Existing Data Collection
Records or Large Databases
Advantages: saves time and money; reduces probs w/ subject recruitment, access, and ethical concerns
Disadvantages: records/data are subject to probs of authenticity and accuracy
Data Saturation
point when data collection can cease b/c info being presented is repetitive and inclusion of additional participants doesn’t result in new ideas
Data Analysis
Search for DOMAINS or SYMBOLIC categories
Theme/Label
represents a way of describing Lg quantities of data in a condensed format
Grounded Theory
SOCIAL PROCESSES AND SOCIAL STRUCTURES
- used to build/Construct a theory where one does not exist (theoretical sampling)
- theory constructed from a base of observations of the world as it is lived by a selective group of ppl
“RESEARCHER AS AN INSTRUMENT” by emersion in direct observation and learning
- Data analyzed w/ CONSTANT COMPARATIVE METHOD
-MODIFIABLE AS NEW INFO GATHERED
Ethnography (cultural knowledge)
Cultural anthropology
Goal: to understand natives of the world
- Scientifically describes and interprets cultural or social groups or systems
- emersion and time spent in setting w/ FIELD NOTES and participant observation
- Essence of method: descriptions of cultural groups or subgroups
Control/Comparison Group
NO intervention or tx
- variables under study held at constant or comparison level
Experimental Group
Receives intervention or tx
Controlling Extraneous and Antecedent Variables
use homogeneous sample
use consistent data collection procedures
train and supervise data collectors and interventionists
- manipulate the IV
- Randomization
Solomon-Four-Group Design
Tests AGAINST threat of internal validity of instrumentation
- Controls for REACTIVE EFFECTS of the pretest
- 2 identical groups used in experimental design, plus 2 additional groups (experimental after and control after)
- subjects randomly assigned to 1 of 4 groups before baseline data collected
- results in 2 groups that only rcv a posttest, which provides opp to rule out result distortions that may hv occurred due to exposure to the pretest
- larger sample size = more $
Longitudinal Studies
Collects data from the SAME group/cohort at DIFFERENT times
- relationships and differences
- repeated measurements
Ex-Post Facto/Retrospective (Case control; comparative;casual comparative)
Looking back
Cross-Sectional Studies Design
Data gathered once w/ 1 pt during a certain time
- can explore comparisons or differences
Survey Studies (DEC)
Descriptive
Exploratory
Comparative
Correlational Studies
DO NOT DETERMINE CAUSE AND EFFECT
Random Assignment controls for…
Selection bias
Limitations also means…
study weaknesses
Threat to Internal Validity MOST DIFFICULT TO CONTROL IS…
MORTALITY, so oversample to have adequate power
Degree to which study results can be applied to the larger population is…
external validity (generalize the findings)
Type of design that controls for the REACTIVE EFFECTS of the PREtest is….
Solomon Four Group
Threat to Internal Validity that is controlled when a researcher completes an experiment in a short period to minimize developmental changes…
maturation
Threat to internal validity that is controlled when a researcher uses reliable and valid assmt tool/scales for rating/scoring to avoid bias…
Instrumentation
True-experiment req’s what…
Control, manipulations, randomization
