BRM Flashcards
(131 cards)
5 levels of evidence strength?
- meta analysis
- experimental studies
- correlational studies (longitudinal and cross sectional)
- qualitative studies
- ad hoc personal observations
2 most important concepts of study design?
validity| reliability
Define validity
Are we really measuring what we say we are measuring?
Define reliability
Can our measure produce the same results everytime?
- Provided the thing we are measuring is not subject to change.
- For example, personality is supposed to be a stable trait and therefore a measure of personality should get the same (or very similar) results when a person is tested at different times.
- However, some things such as attitudes can change and the very point of our study may be to see if a certain intervention changes attitudes.
- For example, we might want to see if we can change attitudes to engaging in pro-environmental behaviours.
Existing data advantages
- If open source it is easy to access.
- Most often does not require lengthy ethical assessments.
- For certain types of study, it is the only practical source of information (see Lecture 2).
Existing data disadvantages
We must think carefully about its validity – is it really a measure of what we think it is?
- Qualitative data needs skilled manipulations - especially in relation to reliability (see Lectures 3 and 4).
Define coding
the process of classifying observables such as behaviours into specifically defined categories for data analysis
What is a code book/scheme?
descriptive document that explains how data has been defined and classified in order to be converted into numerical (often categorical) data
Observational studies - advantages
Observations allow us to study what people actually do.
Observational studies - disadvantages
Can generate enormous quantities of qualitative data.
- It can be hard to decide what is important.
- Can be very difficult and time consuming to convert into data.
- Requires experience to develop reliable data coding schemes.
- If the observer is present (or known about) it can change the behaviour of the observed.
- If the observer is not known about it there are a lot of ethical issues to be addressed.
- Because the participants have not given consent to be observed.
Questionnaires - advantages
- A relatively large number of people’s responses can be collected.
- The participants may be widely geographically distributed.
- Reliable scales can be developed.
- Scales allow direct comparability between subgroups’ responses.
- Or direct comparability at two or more different time points.
They are less time consuming than interviews.
Questionnaires - disadvantages
- They require a lot of skill to do well.
- The issues of concern are pre-determined by the researcher.
- There is no opportunity to explore issues in more depth.
- They have poor response rates.
Interviews - advantages
Allow the researcher to get detailed information about what the participants think.
- Are not totally based on the researchers’ preconceptions and allow follow up of unforeseen issues.
Interviews - disadvantages
- All the same problems as other qualitative data collection techniques, i.e. what to do with large quantities of descriptive data.
- Responses may be affected by the individual interviewer.
- Participants may not want to reveal information about sensitive subjects in a one-to-one situation.
- Very time consuming.
- Often difficult to make comparisons between participants.
Sorting tasks - advantages
Can access the way people think about a specific domain without researchers’ preconceptions.
- Can reveal concepts that participants find difficult to verbalise (e.g. expert knowledge).
- Useful for understanding knowledge outside the researchers’ area of expertise.
sorting tasks - disadvantages
Difficult to initially develop.
- Time consuming.
- Difficult to analyse.
- Only suitable for small samples of participants.15-25
What is a profile?
The results sorted items produce against the categorical measures they are assessing.
It shows the way people think about the items
What is the Likert scale?
an odd number of responses to elicit a response about an emotional attitude or behaviour. usually 1 to 5 or 1 to 7.
What is a t-test?
The t-test assesses whether the means of two groups are statistically different from each other. This analysis is appropriate whenever you want to compare the means of two groups, and especially appropriate as the analysis for the posttest
-only two-group randomized experimental design e.g. time taken to walk in vs out of a dentist
What types of data might we never have?
That which is withheld for security reasons.
- In-house security research has the full data.
- Those of us working in academia have to live with it.
- Develop and test models based on what we have (see Lecture 5 BRM for example).
Where those present are killed.
- Both victims and offenders.
- A potential systematic bias – (e.g. does victim resistance work) – we have little or no data for those cases with the very worst outcomes.
Other biases: Eye witness and victim testimony.
- Victims and witnesses of violent and traumatic incidents have unreliable memory.
- Many academic studies.
What is Crenshaws list?
unofficial list of reputable news sources:
BBC
Telegraph
Observer
Independent
Times
Guardian
Washington Post
New York Times
CNN
Types of media bias
- Occur near to base (theirs),
- Have the potential to affect their own readers,
- Are “unusual”,* Or result in loss of life.
- “Low key” incidents and unsuccessful missions may not be covered.
- Results in public perception that (for example) hijacks don’t happen any more and that terrorism is aimed only at killing people.
- E.g. Many terrorist attacks are against property – but these are rarely reported.
- Is the media “forcing” terrorists to take more serious action?
- Media does not report unsuccessful crimes very often.
Selective reporting makes violent crime seem more prevalent than it really is.
- There is a whole literature on “Fear of Crime”.
- Those who are most fearful are not those most likely to be victims.
- Contagion or Copycat crimes.
- There are a number of crime types that are thought to be prone to so called “contagion” effects.
- There are studies that demonstrate this statistically. - E.g. Hijackings, product tampering, mass shootings. (And suicide).
- News restrictions/blackouts.
Basic issues of media sources
Choose the most reliable news sources possible – “Crenshaw’s List”
- Use more than one account for each crime studied.
- We tend to use three reputable sources and compare the content.
- “Triangulation” of sources.
- What if they don’t agree?
- Two out of three agree? If they all disagree get a fourth.
Press Contradictions on detail - reasons?
Breaking news may not yet have very many details available to report.
- Therefore contradictions between reports may be time related…
- Were the reports published at different stages of the incident meaning new information may have only just come to light?
- This is why for your exercise I said choose reports close to the time the crimes were committed.
- But in real research you will rarely be creating data on breaking news and have time to sample reports over a period of time.
- GTD allows for updates if more information becomes known. But only uploaded once a year.