Research methods Flashcards
Introduction to RM, descriptive stats, presenting data, research approaches, organisational designs, probabilities
methodology
the study of methods
method
how to reach a certain goal
epistemology
what is knowledge
ontology
what is reality
philosophy of science
what is science?
why do i need research methods?
limit bias of perception, imperfect memory (cognitive),
prior experience and learning,
create a scientific method
challenges in psychological research
- unobservable object of investigation
- subjectivity of object of investigation
- social construction (phenomena occurs in environment)
- ethics
types of research
basic research - to increase the stock of knowledge.
applied research - to increase the use of knowledge to devise new applications.
stats in psychology
clinical, diagnostics, development, neuroscience and cognition
allow for discovery, modelling and scientific proof.
the difference between a belief and knowledge
belief- subjectively true
knowledge- objectively true
the research method is a way to check for proofs and obtain knowledge
scientific research
building knowledge using specific research methods to check for proofs
should be
- transparent
- share expertise
hypotheses vs conclusions
a hypothesis is an unproven provisional statement
a conclusion is a proven proposition
scientific proof
logical proof- does it make sense (rationalism)
empirical proof- is there evidence (empiricism)
the process - logical arguement - empirical test - logical argument
logical argument (causal influence)
3 types of causal influence:
- necessary cause- the cause is to produces the effects
- sufficient cause- the cause alone produces the effect
- contributory cause - this contributes to the cause producing the likelihood or strength.
criteria of scientific propositions
- logical consistency
- testability
- scope
- fruitfulness
- novelty
- simplicity
- conservatism
logical consistency
3 types of logical inference:
- deduction - infer info about a single case
- induction - infer a general statement from statements about single cases
- abduction - infer cases the most likely best explanation
testability
how well it can be tested
scope
general validity
fruitfulness
implications beyond the research question
novelty
information which is new and creating propositions
simplicity
parsimony - minimise assumptions by creating the most simplistic and scientific explanation
conservatism
minimise new assumptions that contradict existing knowledge. propositions that integrate with existing knowledge and more likely because it is unlikely to be wrong.
theory before the empirical test
theory - research question - assumption - hypothesis - prediction
theory after empirical test
data analysis - conclusion - implications.
level of measurement of data
nominal, ordinal, interval or ratio
nominal data
categorical data of groups, have to be mutually exclusive (not part of two groups), can’t order the data
ordinal data
orders people, objects or events along some continuum (various rankings), no information is given about the differences between the points on then scale
interval data
equal intervals between objects represents equal differences, interval scales do not talk about ratios (zero is arbitrary)
eg temperatures
ratio data
ratio data has a true zero point eg the absence of something being measured eg weight
descriptive statistics
goal to characterise a numerical set of data efficiently and representatively, condense and render meaningful information, minimise error involved in condensing information
inferential statistics
the goal is to infer the characteristics of the population from a sample so generalise the results
measures of central tendency
mean, median and mode
mean
the average score, add up all the scores and divide by the number of scores. mean can be influenced by the anomalies. a histogram can show whether the mean is a good measure
median
middle score when all do the scores are rearranged in order from smallest to largest, not affected by extreme scores
(N+1)/2
mode
the value with the most frequent score, if two adjacent scores find the middle eg 4 and 5 = 4.5, if two non adjacent scores report the, both eg 4 and 7 (bimodal distribution)
measures of variability
the degree to which the values vary: range, interquartile range, variance and standard deviation
range
the difference between the maximum and minimum scores, measure of distance, easily distorted by outliers
interquartile range
percentiles - cut off that divides the data into percentage chunks
percentiles can try to avoid anomalies. 50th percentile splits the data into percentage hard so 50% scores above and below.
0.5(N+1) = 50th percentile
0.75(N+1) = 75th percentile
variance
how much the mean scores vary given in
terms of the distance from the mean
the average of each score’s squared deviation from, the mean score
sample vs population
population- use the population formula (divide by N)
sample- use the sample formula (divide by N-1)
experimental control
casual effect - is what’s wanted to be measured
noise - unwanted
confounders - unwanted
noise
random variation which is uncertain
signal
systematic, regular and informative
bias
unwanted or unexpected signal (e.t. systematic variation, systematic tendency) producing spurious results
consequence- measurements without (real) experimental effects differ from what you assume and expect. discrepancies between results and facts
types of bias
independent bias and dependent bias
independent bias
systematic errors,
systematic tendencies (signals) in measurements that are incorrect but limited to one variable
bias does not vary with the independent variable hence can’t be mistaken for causal effect (results)
dependent bias
cofounder
a confounder produces bias in the dependent variable (DV) that varies with the experimental conditions (IV)
this bias is correlated with both independent and dependent variables - interfere with causal effects (results)
produces an unwanted, spurious effect on measurements (DV)
systematic errors
unwanted signal bias that does not interfere
criteria of empirical evidence
noise - reduce reliability, reduce accuracy
systematic errors - reduce accuracy
confounders - reduce internal validity and reduce external validity
sources of noise and bias
- method (stimulus material and procedure)
- participant (variation of physical condition e.g. fatigue, perception, emotion and cognitive processing)
- data recording (variation of experimenter or measurement instruments)
minimise systematic errors
easy to fix or compensate through CALIBRATION - comparison with and adjustment measure
why control noise?
noise decreases the accuracy and reliability of measurements:
- results of single measurements are inaccurate due to random variation
- more random variation the less likely it is to get the same results across measurements
aim of controlling noise:
maximise systematic variation (signal) due to causal effects relative to random variartion (noise) - single -to -noise -ratio
want to maximise the ratio
how to control noise?
- minimise (aka maximise precision)
- neutralise (e.g. maximise sample size)
minimise
- instruments with high precision
- tasks with high precision
neutralise
take an average of the frequencies - approach the frequencies based on probability
neutralise by sample size
if noise is uniformly random, increasing the sample sizes makes the average coverage to the expected value
expected value of noise is the same for all conditions
central tendency of larger datasets involve less noise
how to neutralise by sample size?
increase number of participants
increase number of measurements per participants
noise and statistical reliability
signal-to-noise-ratio
- the amount of desired signal (e.g. experimental effects) relative to the noise
- the higher the SNR the higher the sensitivity and the specificity of your measurement
agency
human beings (agents) act upon and shape their environment
interpretation
people perceive, think and make choices to adapt their actions and behaviour
interaction
human beings act on other acting human beings - they mutually influence their behaviour
double-interpretation
one person interprets how another person interprets and acts accordingly, which may in turn influence the interpretation and action of the other person
social construction
interpretation and meaning exist because of the coordination with others rather than separately within each individual, based on mutual expectations
double-hermeneutic
concept from sociology, Giddens, 1970
participants interprets the researchers behaviour and setting of the study and adapt their behaviour
agency in psychology
- investigators influence participants in studies
- participants influence the interpretation by the investigator
- not limited to direct communication
agency-based biases in research
- participant effects
- investigator effects
participant effects example
Hawthorne studies
- aim to increase performance of factory workers
- manipulation - changing lighting, cleaning workstations, clearing floors and relocating workstations
Hawthorne effect
- productivity gain as a result of increasing worker motivations because of the interest being shown in them
participant effects: general idea
participant reactivity
- the act of doing the research changes the behaviour of participants
- due to awareness of the, being observed by the researcher or by other participants
- response bias (unconsciously it could happen)
response bias
- systematic tendencies of participants to respond inaccurately or falsely, producing either a systematic error, or a confound (if mixed with investigated effects)
- participant reactivity - only one of different types of response biases due to the location of response keys
types of participant effects
- participant expectancy
- demand characteristics
- social desirability
- stereotype threat
participant-expectancy effects
participant expects a result and therefore unconsciously affects the outcome or reports the expected outcome
placebo effect
positive expectations about a treatment improve patient-reported outcomes
placebo effect
placebo is a substance or treatment, which is designed to have no therapeutic value
Nocebo effect
negative expectations about a treatment cause negative effects
demand characteristics
participants form an interpretation of the study’s purpose and subconsciously change their behaviour to fit that interpretation
please-you effect
- ppts try to fulfil the expectations of the researcher to please them
screw-you effects
- ppts are defiant and try to produce unexpected results that screw up the study
social desirability bias
tendency to answer questions in a manner that is expected to be viewed favourably by others and that produces or maintains a publicly acceptable image
examples:
- bradley effect: consider voting for a black candidate heavyset it is socially desirable but in the end they don’t vote for them
- evaluation apprehension: when being observed ppts feel evaluated and try to convey a positive image
- watching-eye effect: when being observed, ppts try to behave better than without observation
stereotype threat
responses are biased to conform to stereotypes about the ppts social group
negative effects:
negative stereotypes about your own group produce self-doubts and negative expectations towards yourself
positive effects:
stereotype boost: perceive yourself better because of positive stereotypes about your own group
sterotype lift:
perceive yourself better because of negative stereotypes about an outgroup
control of participant effects
- minimise
- assess
- account for
minimise participant effects
- blind procedures
- information is withheld until after the experiment
- unobtrusive manipulations and measures: conceal IV and DV so no clue on hypothesis
unobtrusive methods:
-unobtrusive observational data recording
- unobtrusive observation
ethical issues:
- no consent
- risks to ppt and researcher
deception: deceived ppt about one or more aspects of the research to conceal the hypothesis
assess participant effects
- post-experiment questioning
- did they know what was expected
- questionnaires e.g. Perceived Awareness of the Research Hypothesis (PARH) scale
account for participant effects
- control conditions
- everything is the same as in the experimental condition except the experimental manipulation
- baseline results: reference measurement for comparison with experimental conditions
control group
- everything same as in experimental condition except IV
randomised control trials (RCTs)
- typically ppts are randomly allocate to the groups in a randomised control trial - if not quasi
placebo control groups:
- create positive expectations with placebo to establish comparability with treatment groups
investigator effects
influence of researcher on results
primary observer effect- effects on participant responses
secondary observer effect- effects on data acquisition and interpretation
primary observer effect
researchers expectations about the findings of their research are conveyed to ppt and their responses
examples: experimenter-expectancy and self-fulfilling prophecies
clever hans effect
shows the primary observer effect
the horse could “count” but it was just the horse responding to the involuntary cues in the body language of the human trainer and audience
self-fulfilling prophecies
behaving so that what you expect will become true
pygmalion effect
one’s expectations become reality like pygmalion’s sculpture coming into life
golem effect- negative effects (low expectations lead to poor performance)
rats in the maze example
self fulfilling prophecy
- rats that were expected to be good actually performed better
secondary observer effect
the researchers select and handle the data in a subjective and bias
happen during data sampling, recording , analyses and interpretation
biases due to secondary observer effects:
sampling bias
observer bias
selection bias
observer bias
systematic divergence from accurate facts during observation and recording of data
- confounders distort data
- researchers observe and record information differently
types of observer bias:
cognitive biases
detection biases
cognitive biases
researchers cognitive bias distort data collection
types of cognitive bias include confirmation buas and halo effect
confirmation bias :tendency to search for, interpret, favour and recall information in a way that confirms their beliefs or hypothesis
halo effect:
tendency for the positive impressions and beliefs in one area to influence a researchers data recording or interpretation in other unrelated areas
detection biases:
focusing on some cases to the detriment of others (e.g. checking diabetes in obese people and not other patients
detection biases can involve cognitive biases (the researcher’s focus) and or errors in sampling
control of investigator effects
- minimise
- assess
- control
minimise investigator effects
double blind procedures
- ppt and researcher are unaware of allocation to experimental condition and cannot anticipate any result
^ counteracts demand characteristics and primary observer effects
assess investigator effects
observer reliability
- indicates how consistent or reliable measurements are
- inter-observer reliability - across different observers
- intra-observer reliability - within observer (retest-reliability
account for investigator effects
averaging across several researchers compensates for individual idiosyncrasies and biases, like when using a jury for ratings
summary link to validity
accuracy and reliability:
- systematic and unsystematic errors
internal validity
- measurements do not measure what they are meant to measure e.g. placebo effects
external validity
- results are not reproducible without experiment specific conditions
representativity of measurements (representativeness)
are measures of the experiment representative of the conditions you want to understand (external validity)
statistical population
the entire pool (or set) of people, items or events ability which a researcher wants to gain insight and draw conclusions in a study
statistical sample
a set of individuals or objects collected or selected from a statistical population by a defined procedure
sampling
the selection of a subset of individuals from within a statistical population to estimate characteristics of the whole population
representativity of a sample
complete sample:
- all members of the population, usually impossible to measure
representative sample:
- represents all relevant properties of the whole population so we can draw conclusions about the population based on measurements
- statical technique allows us to estimate the situation for the whole population based on the measured obtained from representative samples
sampling bias
- systematic error (bias) in sampling causing members of the intended population to be less likely be included in the sample
- undermined external validity - generalisation about the population
sampling bias
- inclusion in measurements
- miss important subpopulations in sample
- in process of gathering sample
- contradicts assumptions and research question
- distorts data and conclusions
- mainly external validity - undermines generalisation of findings beyond context of study
selection bias
- inclusion in statistical analysis
-discard outliers that are
selection bias
- inclusion in statistical analyses
- discard outliers which are meaningful
- after measurements (analysis)
- contradicts experimental design (control and manipulation)
- distorts statistical results and conclusions (data is ok)
- mainly internal - undermines interpretation of results within context of study (confound)
types of causal influence
necessary cause
sufficient cause
contributory cause
necessary cause
the cause is necessary to produce the effect (but might not be sufficient)
bananas must be ripe to taste good, but not all ripe bananas taste good
sufficient cause
the cause alone produces the effect, but it might not be necessary
bananas from kenya always taste good (but there are other good bananas)
contributory cause
the cause contributes to an effect by increasing its likelihood or strength
chocolate sauce increases the flavour of bananas, but if they are not ripe they are still not good, and there are ripe bananas that taste good even without chocolate
standard deviation
the square root of the average of each scores squared deviation from the mean score
the square root of variance
bigger value is more spread out
probability
ranges from 0-1
p(event A) = A/(A+B)
p(event A doesn’t occur) = B/(A+B)
mutually exclusive
occurrence of one event precludes the occurrence of another event
independent events
occurrence of one event has no effect on the probability of the occurrence of another event
additive rule for mutually exclusive events
the probability of occurrence of one event or another is equal to the sum of their separate probabilities
p(A or B) = p(A) +p(B)
clue OR
multiplicative rule for independent events
p(A and b) = p(A) x p(B)
clue AND
rules of and vs or
AND- multiply probabilities
OR- add their probabilities
addictive rule when not mutually exclusive
p(A or B) = p(A)+p(B)-p(A and B)
e.g. when picking a jack or a diamond have to take out the card which is both a jack and a diamond
multiplicative rule for non-independent events
p(A and B)= p(A) x p(B|A)
conditional probability - probability of one evnt given the occurrence of another p(B|A)
combinations
number of ways to arrange a subset of objects
NCr =(N!)/(r!(N-r)!
N is number of events
r is number of successes
! is multiply by all smaller integers
binomial distribution formula
calculates combinations and probability for any one combination of getting r out of N
when b number of events (N) is large the binomial distribution is equal to the normal distribution
binomial distribution formula
p(r) = N!/(r!(N-r)! p^r (1-p)^(N-r)
three ways of presenting results
text- verbal description - establish unambiguous logical relationships, could get lost in details
table- spatially organised representation of single, precise specifications - communicate large number of details, could get lost in details, arguments are not communicated
Graphics- visualisation of trends - focus and highlight main patterns of data, communicate different types of data - specific details e.g. decimals get lost - visual interpretation depends on viewer
data tables
organise information
communicate details
why use graphics?
Assess the quality of data:
- detect faults in experiment (bugs, incorrect data recording, misleading instructions, task too difficult)
- characterise data distribution (normal distribution, skew, kutosis)
- identify outliers (single data points outside the distribution that can be misleading
visualise results:
- highlight main results (test of main prediction)
- explain main results (reveal origin of results, expose spurious results, confounds)
How to make graphics?
1 Dimension - List, rank, line - no gain of visualisation
2D- Area - visualise patterns
3D - Relief, animation, interactive graphic - visualise complex relationships - difficult to interpret
4D - animation, interactive graphic - visualised complex relationships, difficult to interpret
how to use graphical tools?
- how many variables
- what types of variation
- what scale
- what resolution
- what pattern or relationship