PSYA01H3 Chapter Notes - Chapter 2: Operational Definition, Random Assignment, Descriptive Statistics
Chapter 2:
Characteristics of Quality scientific research:
1. It is based on measurements that are objective, valid, and reliable
2. It can be generalized
3. It uses techniques that reduce bias
4. It is made public
5. It can be replicated
Scientific Measurement: Objectivity
• The foundation of scientific methodology is the use of objective measurements
• Objective measurements: The measures of an entity or behaviour that within an
allowed margin of error, is consistent across instruments and observers
• Variable: the object, concept or event being measured
• Operational definitions: Statements that describe the procedure or operations and
specific measures that are used to record observations
• Validity: Refers to the degree to which an instrument or procedure actually measures
what it claims to measure
• Measurement tool: Demonstrates reliability when it provides consistent and stable
answers across multiple observations and points in time
Test - retest reliability: examines where scores on a given measure of behaviour are consistent
across test sessions
Alternate - forms of reliability: takes place when observers have to score or rate a behaviour or
response
• Ex. Patient in an hospital are given 2 different sets of word simply because test-retest
might be a result of practicing to get better
Third type of Reliability: takes place when observers have to score or rate a behavior or
response
• One or more person must do the rating, otherwise it is impossible to determine if the
responses were accurately measured or if the results were due to the single rater
• Having more than one rater allows you to have inter – rater reliability, meaning that the
raters agree on the measurements that were taken
• Reliability and Validity are essential components of scientific research
Generalizability of research:
• Generalizability: refers to the degree to which one set of results can be applied to other
situations, individuals or events (study in a large group of participants)
• Population is the group that researches want to generalize about
• Sample is a select group of population members, once the sample has been studied,
then the results may be generalized to the population as a whole
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Random sample: a sampling technique in which every individual of a population has an equal
chance of being included
• Not always possible to use random sampling
Convenience samples: are sample of individuals who are the most readily available, for
example, introductory psychology students
• Psychological research should generalize across time and location
• Researchers should ideally have high ecological validity
Ecological validity: meaning that results of a laboratory study can applied to or repeated in the
natural environment
• Researchers should ideally have high ecological validity
Sources of bias in psychological research:
• Researcher Bias: are unintentional bias introduced by the researches
• Subject or participant bias: where a participant of the experiment introduces their own
biases usually out of attempting to predict the response researchers are looking for
• Hawthorne effect: a behaviour change that occurs as being observed
• Social desirability: respond in a way that increase the chances that they will be viewed
favourably by the experimenter and or other participants
• Demand Characteristics: are inadvertent cues given off by the experimenter or the
experimental context that provides information about how participants and expected to
behave
• Placebo effect: a measurable and experienced improvement in health or behavior that
cannot be attributable to a medication or treatment
Techniques that reduce bias:
• Best techniques for reducing subject bias is to provide anonymity and confidentiality to
the volunteers
• Anonymity: eah idiidual’s esposes ae eoded ithout a ae o othe
personal information that could link a particular individual to specific results
• Confidentiality: results will only be seen by researcher (efficient for sensitive issues such
as sexual history and etc.)
• Single – blind study: the participants do not know the true purpose of the study, or else
do not know which type of treatment they are receiving
• Double – blind study: a study in which neither of the participants nor the experimenter
knows the exact treatment for any individual
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Sharing results:
• Peer review is a process in which papers submitted for publication in scholarly
journals are read and critiqued by experts in the specific field of study
• Academic journals are a primary source of communication
Replication:
• Replication: process of repeating a study and finding a similar outcome each time
Five characteristics of poor research:
1. Untestable hypothesis: for a hypothesis to be testable if must be falsifiable meaning
that the hypothesis is precise enough that it could be proven false (if not, then it meant
that there is always a way to reinterpret the results to make the hypothesis match the
data)
2. Anecdotal evidence: a idiidual’s sto o testio aout a oseatio o eet
that is used to make claim as evidence
3. A biased selection of available data:
4. Appeals to authority: the elief i a epet’s lai ee he o suppotig data o
scientific evidence is present
5. Appeals to common sense: is a claim that appears to be sound, but lacks supporting
scientific evidence
2.2 Scientific research designs
Research design: a set of methods that allows hypothesis to be tested
1. Organize stimuli used to test hypothesis
2. Make observations
3. Evaluate the results
Common characteristics of research designs:
• Variables: a property of an object, organism or event, or something else that can take
on different values. How frequently you laugh is a variable that could be measured and
analyzed
• Operational definition: details that define the variables for the purpose of a specific
stud. Fo sese of huou, this defiitio ight e the soe o the opig huo
sale
• Data: scientist collect observations about the variables of interest, the information they
record is called data. Ex. Data might consist of the collection of scores on the coping
humour scale from each individual in the sample
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