Scientific Processes Flashcards
Sampling
portion of a target population should be representative with same characteristics
Random sampling
Everyone has the same chance of selection
+ likely representative, no bias, easy
- not all chosen can participate, hard to get a full list of all population
Systematic sampling
Select every nth person
+ simple, can be representative
- may skip over periodic traits, need sample frame, not all chosen can participate
Stratified sampling
Divide based on characteristics and get same proportion sample as population strata
+ most representative
- very time consuming
Opportunity sampling / convenience
Selecting readily available participants such as certain groups of people in contact e.g friends
+ easiest and possible method to ensure large samples
- not representative and some may feel obliged to take part
Volunteer sampling
People volunteer e.g in response to an advert
+ saves time and effort as you just make an ad then wait
- participant variables as some types of people much more likely to volunteer for reesearch
Conditions
Control - no change used as a baseline comparison
Experimental - exposed to IV
Controls
Randomisation - chance order to reduce bias e.g picking word list order randomly - esp for repeated measures
Random allocation - similar but instead chances of participants being in a condition in independent groups
Standardisation - exact same procedures and instructions to improve reliability - e.g following a script
Independent groups design
equal participants randomly allocated to different conditions
+ no order effects, less demand characteristics as harder to find aim, not lost between repeats
- more people needed, individual differences
Repeated measures design
all participants partake in all conditions
+ half as many people needed, no individual differences
- order effects (can be avoided by counterbalancing, half do A first half do B first), demand characteristics as easy to guess aim
Matched pairs design
Different participants matched between groups based on characteristics
- no order effects and less individual differences
+ difficult matching process, more participants needed, individual differences can still manifest - not very observable
Reliability
consistency by repeats
external when consistent over time - test retest if similar results then reliable
internal reliability - consistent within itself - e.g split half technique for questionnaires see if results consistent between two halves of participants
Validity
Measures what it intended to
External/ ecological - generalisable to other settings/ real life
participant validity - can be generalised to target population
temporal - generalised to todays contemporary society
internal validity - if cause and effect is clear and no EV
Controlling EV
Participant variables - overcome by matched pairs and repeated measures (with random allocation and counterbalancing)
Situational variables - keep environment same e.g noise, heat and standardisation so sameconditions
Experimenter variables - factors of experimenter effecting DV e.g appearance and conduct - standardised instructions and scripts
Investigator effects
Characteristics like age, ethnicity can influence behaviour of participants
or investigators own knowledge leads to bias in collection and interpretation - observer bias and interviewer effecs
Can be overcome by double blind where nobody knows aim of study
Demand characteristics
guess aim leading to changed behaviour and social desirability bias or just to annoy researches - overcome by single blind ensuring they don’t know aim
Ethical issues
ethics committee with staff, psychologists, public members to approve research proposals if they are properly suited for ethics. BPS british psychological society publishes a code of ethics with rules for research
Ethics code
Introduction ( establishes necessity) , general (establishes need to consider from all viewpoints), fully informed consent, deception (avoid unless necessary), debrief (with intervention), right to withdraw (communicated + given), confidentiality (consent to share data), protection from harm (no more than usual), giving advice (if underlying problems uprooted)
Informed consent
Informed what is required, purpose, right to withdraw
ask an adult or next of kin if below 16 or mentally unable
presumptive - if a similar group of people consented they should too
prior general - given consent quite some time ago (for a ‘future’ study)
retrospective consent - asking after experiment (if no then data destroyed)
Deception + debriefing
withhold info from participants - may be necessary if it will affect results e.g demand characteristics. ethics committee conduct cost benefit analysis to see if worth deception
debriefing must be done after to explain what the real study was, allow questions to be asked and given options to remain confidential/ withdraw
How to write a consent form
Detail what the study is about and what they need to do, explain some ethical issues that are present to see if they are willing anyway, have proper letter form e.g space to sign and data and dear sir/madam
Why is peer review necessary
To ensure validity and reliability of research
Peer review process
complete research, then university sends work to other(s) in similar field to scrutinise, if good enough then will be publish in psych journal with peer review report, considered by a research panel
Double blind process where they dont know who is reviewing whos work
If not good enough then sent back to improve, though some journals like Nature and Science are very prestigious so unlikely to approve
Open access
Academic journal expensive and barred from public
Open access - community views online where anyone can review it - readers can see easily and make comments/ ratings on blogs and online journals - still some work rejected if unsatisfactory
Why should psych work be published
Appears in journals used internationally to help establish new theories/ research
Confidence that work is good quality
Increase reputation and funding of researcher and uni
Government grants for research so more money
Parliamentary office of science and technology - main functions of peer review
allocation of research funding(both by gov and charities)
publication in academic journals (proves quality and can claim credit)
assess research rating of uni departments (hence e.g Russell group status)
