primary and secondary data. secondary data pre-existing data not gathered for purposes of the...
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Secondary DataPre-existing data not gathered for purposes of
the current research
Not ‘new’ data – ‘second hand’
Secondary data
‘Back up’ data – secondary in use
•Data gathered by another source (e.g. research study, survey, interview)
•Secondary data is gathered BEFORE primary data. WHY?
•Because you want to find out what is already known about a subject before you decline into
your own investigation. WHY?•Because some of your questions can possibly
have been already answered by other investigators or authors.
Advantages and DisadvantagesAdvantages• Resource implications – usually easier to gather than
primary data• Unobtrusive – already collected• Longitudinal study may be possible• Quality and permanence of data – eg. government
surveys
Disadvantages• Suitability• Cost and access – may still be difficult in spite of
resource advantages • Validity of some secondary data (eg. Internet sources)
Primary Data
• Data never gathered before.• Advantage: find data you need to
suit your purpose• Disadvantage: usually more costly
and time consuming than collecting secondary data
• Collected after secondary data is collected
Types of Primary Data• Demographic/Socioeconomic
– Age, Sex, Income, Marital Status, Occupation• Psychological/Lifestyle
– Activities, Interests, Personality Traits• Attitudes/Opinions
– Preferences, Views, Feelings, Inclinations• Awareness/Knowledge
– Facts about product, features, price, uses• Intentions
– Planned or Anticipated Behavior• Motivations
– Why People Buy (Needs, Wants, Wishes, Ideal-Self)• Behavior
– Purchase, Use, Timing, Traffic Flow
Primary Data Can Be Gathered By:
• Communication Methods– Interacting with respondents– Asking for their opinions, attitudes,
motivations, characteristics
• Observation Methods– No interaction with respondents– Letting them behave naturally and drawing
conclusions from their actions
Communication Methods of Primary Data Collection
• Methods include:– Surveys– Focus Groups– Panels
• Highly versatile in terms of types of data• Generally more speedy• Typically more cost effective
– Electronic media have made observation cheaper– Activities, Interests, Personality Traits
Pros and Cons of Telephone as a DataCollection Method
• Relatively fast• Relatively strong
response rates, but getting worse
• Sequence of questions can be easily changed
• Data entry at time of completion is possible
• Ability of supervisor to oversee interviewers
• Does not handle long interviews well
• Cannot use visuals• Difficult to contact
business respondents• Unlisted numbers make
sample frame questionable
Pros and Cons of Mail as a Data Collection Method
• Easy to generate stratified sample frame
• No interviewer bias• Assures anonymity of
respondent• Wide distribution • Best for sensitive or
personal questions• Generally least
expensive
• Little control over exactly who completes survey
• Low response rate• Long response time• No ability to probe on
open-ended questions• Cannot change
sequence of questions
Sampling Techniques
Population - total group of respondents that the researcher wants to study. Populations are too costly and time consuming to study in entirety.
Sample - selecting and surveying respondents (research participants) from the population.
Sampling Techniques
A probability sample is one that gives every member of the population a known chance of being selected.– simple random sample - anyone– stratified sample - different groups (ages)– cluster sample - different areas (cities)
All are selected randomly.
Sampling Techniques
A non-probability sample is an arbitrary grouping that limits the use of some statistical tests. It is not selected randomly.
• convenience sample - readily available
• quota sample - maintain representation
Personal Interviews as a Data Collection Method(in-home and mall intercept)
• Probably highest response rate
• Allows any type of questions/questionnaires
• Easy to ensure representative sample
• Know who is completing questionnaire
• Mall intercept can be relatively quick
• Generally narrow distribution
• Typically most expensive method
• Often tough to gain identity of respondent
• Can be time consuming in the case of in-home
• Tough to supervise
Constructing the Questionnaire
Select the correct types of questions:• open ended – harder to score but get
“richer” information• closed ended, dichotomous – offer
two either/or responses (true/false; yes/no; for/against
• multiple choice – select one or more than one
• scaled response – gather range of “values” (strongly disagree, somewhat disagree, neutral, somewhat agree, strongly agree
1. Have you had any of the following medical preventive tests/exams?
_____ mammogram (if a women)
_____ prostate exam (if a man)
_____ lung x-ray
_____ electrocardiogram
_____ stress test
3. Please evaluate the following statement:
I understand the University’s code of conduct as it relates to plagiarism.
____absolutely agree
____somewhat agree
____neutral
____somewhat disagree
____absolutely disagree
Important characteristics of good questionnaires
• Plan a user-friendly format• Gather demographic data – age, gender,
etc., when necessary. • Guarantee anonymity• Ensure ease of tabulation – Scantron forms• Ask well-phrased and unambiguous
questions that can be answered• Develop for completeness – get all the
data• Pilot test the instrument
Electronic Media as a Data Collection Method(email, online, fax)
• Typically low cost, especially marginal cost of additional responses
• Wide distribution possible
• Very quick (15 minutes-2 days)
• Fairly decent response rates
• Easy point-of-purchase feedback
• Automatic data entry
• Limited sample frame– representative
– ability to locate
• Expense of infrastructure and expertise
• SPAM backlash
• Legal problems
Increasing Response Rates for Communication Methods
• Pre-notification letters
• Cover letters/purpose statements
• Incentives– Money– Donations to charity– Gifts
• Postage-paid returns
Observation Methods: What Can Be Observed?
• Physical Actions
• Verbal Behaviors
• Expressive behaviors
• Special Relations and Locations
• Temporal Patterns
• Physical Evidence
Primary Research Methods
• Focus Groups – bring together respondents with common characteristics
• Observation - actually view respondents• Experiment - controlled variables and
respondent groups.• Non-personal survey – on site, telephone,
mail, fax, computer, panel• Personal interview - one-on-one survey
with respondents• Company records – internal document
survey research
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