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Research > Chapter 10 - Sampling & Data Collection in Quantitative Studies > Flashcards

Chapter 10 - Sampling & Data Collection in Quantitative Studies Flashcards

1
Q

What is the population?

A

The entire group of interest

The collection of elements/cases in which a researcher is interested in

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2
Q

What is a sample?

A

a section of a portion of the population to represent the entire population

A subset of population elements→ elements are usually humans

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3
Q

What is eligibility criteria? Inclusion vs. exclusion criteria

A

specific characteristics to define the population

Inclusion criteria: characteristics that make one a member of the population

Exclusion criteria: characteristics that cause one to be excluded from population

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4
Q

Target population

A

the entire population in which a researcher is interested (ex. all diabetics in the US)

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5
Q

Accessible population

A

portion of the target population that is accessible to the researcher (ex. all diabetics at one hospital)

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6
Q

Strata

A

mutually exclusive segments of a population based on specific characteristics
(Ex. RNs in the UK can be separated by GENDER, Years of experience)
–> Strata are often used in sample selection to enhance the samples representativeness

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7
Q

Representative Sample

A

one whose characteristics closely approximate those of the population

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8
Q

Sampling Bias

A

systematic overrepresentation or underrepresentation of some segment of the population in terms of key characteristics when the sample is not representative
–>can be risky to apply it to the population because it could be very incorrect

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9
Q

A representative sample is most easily achieved with… (3 things)

A
  1. Probability sampling – sampling at random
  2. Homogenous populations – more alike than different
  3. Larger samples – people in sample are more likely to have the characteristics you are looking for
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10
Q

Nonprobability Sampling

A

researchers select elements by nonrandom methods in which every element usually does not have a chance to be included

  • rarely produce representative samples
  • MOST research samples in nursing are nonprobability
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11
Q

Convenience Sampling

A

selecting the most conveniently available people as participants
-problem: atypical population, bias –> weakest form of sampling

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12
Q

Quota Sampling

A

identify population strata and figure out how many people are needed from each stratum –> ensures diverse segments are accurately represented

-participants are a “convenience sample” from each stratum

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13
Q

Consecutive Sampling

A

recruiting ALL people from an accessible population over a specific time interval or for a specified sample size

  • longer sample time = less bias due to seasonal fluctuations
  • best choice when their is “rolling enrollment” in population

–>ex. ICU patients admitted over 6 months, or the first 250 patients

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14
Q

Purposive Sampling

A

based on the belief that researchers’ knowledge about he population can be used to hand-pick sample members

  • can lead to bias (based on purposeful judgement of the researcher)
  • useful when you want a sample of experts
  • mostly qualitative
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15
Q

Probability Sampling

A

involves random selection of elements form a population - all elements have equal chance of being selected

  • random sampling
  • only viable method of obtaining representative samples, can easily estimate sampling errors (ex. average age of population) and sample values (ex. average age of the sample)
  • often impractical
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16
Q

Random Sampling

A
  • used on probability sampling

- ->each element in the population has an equal, independent chance of being selected

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17
Q

Simple Random Sampling

A

most basic probability sampling

  • researchers establish a sampling frame (list of population elements –> ex. student roster for sampling students at MU, pulling names out of a jar)
  • no guarantee of a representative sample, but there is no researcher bias (sample of CHANCE)
18
Q

Stratified Random Sampling

A

population is first divided into two or more strata, from which elements are randomly selected

  • ->ex. sex, ethnicity
  • aim to enhance representativeness
  • only works if stratifying variable is available
19
Q

Systematic Sampling

A

selection of every “kth” case from a list (ex. every 10th person on a patient list)
-divide population into sampling interval and then select sample from different intervals

20
Q

Sample Size

A

the number of study participants in the final sample
LARGER is better = less sampling error
-Sample size adequacy needed for quantitative research

21
Q

Power analysis

A

helpful in estimating how large their samples should be for testing their research hypothesis
–>when predicted differences are small - a large sample is needed

22
Q

What are the two issues to assess when critiquing a sampling plan?

A
  1. Has the researcher adequately described the sampling strategy?
  2. Has the researcher made good sampling decisions?
23
Q

Ideal description of the sampling strategy

A
  • The type of sampling approach used
  • The population under study and eligibility criteria for sample selection
  • The sample size, with a rationale
  • A description of the samples main characteristic (age, gender, clinical status)
  • The number and characteristics of potential subjects who declined to participate
24
Q

How do you know if the researcher has made good sampling decisions?

A
  1. Response rates: the number of people who participated in a study relative to the number of people sampled
  2. Nonresponse bias: differences between participants and those who declined to participate (response bias)
    - ->In longitudinal studies attrition (dropping out) bias should be reported
25
Q

Data Collection: New data vs. old data

A

New data – data collected specifically for research purposes (primary data)

Existing data – records, historical data, existing data sets (secondary analysis)

26
Q

Self-Report

A

participants’ responses to questions posed by the researcher

  • ->best when researchers know in advance exactly what they need to know and can frame appropriate questions needed to obtain needing information
  • most common in nursing studies
  • direct observation may be used
27
Q

Closed-ended questions

A

response alternative are prespecified (ex. yes or no)

  • good closed ended questions are difficult to construct but easier to analyze, more efficient
  • may be superficial
28
Q

Advantages of Questionnaires

A
  • less costly
  • can be dispersed anywhere easily (especially over internet)
  • possibility of anonymity
29
Q

Advantages of Interviews

A
  • more than questionnaires
  • response rates are higher (don’t refuse to talk to an interviewer as much)
  • interviews are feasible with most people (many cannot fill out a questionnaire - children, blind, elderly)
  • interviewers can produce additional info through observation of responders behavior/living situation
30
Q

What is a scale?

A

a device that assign a numeric score to people along a continuum (ex. scale for measuring weight)
–>social-psychological scales quantitatively discriminate among people with different attitudes, perceptions, and psychological traits

31
Q

Likert Scale

A

several declarative statements (items) that express a viewpoint on a topic
–>express how much you agree or disagree with a statement

Summated Rating/Composite Scale: sum of item scores

32
Q

Visual Analog Scale (VAS)

A

used to measure subjective experiences (ex. pain, dyspnea)

  • a straight line with end anchors that are labeled as the most extreme limits (no pain vs. worst pain ever)
  • should be 100 mm in length = score of 0-100
33
Q

Social Desirability Response Set Bias

A

a tendency to misrepresent attitudes or traits by giving answers that are consistent with prevailing social views

34
Q

Extreme Response Set Bias

A

a tendency to consistently express extreme attitudes or feelings (ex. strongly agree) leading to distortions because extreme responses may be unrelated to trait being measured

35
Q

Acquiescence Response Set Bias

A

a tendency to agree with statements regardless of their content by some people (yea-sayers) or disagree with statements independent of the question’s content (nay-sayers)

36
Q

What areas do observational researchers have flexibility?

A
  1. Focus of observation - broad (events) or narrow (specific behaviors - facial expressions)
  2. Concealment - may not tell subjects they are observing (reactivity: behavior distortions because they know they are being watched)
  3. Method of recording observations - paper and pencil recording or sophisticated methods (ex. video, audio, computers)
37
Q

Category System

A

represents a method of recording in a systematic fashion the behaviors and events of interest that transpire within setting

Non-exhaustive: all observed behaviors are classified into one category
Exhaustive: many behaviors in many categories

38
Q

Rating scale

A

observers rating phenomena along a descriptive continuum (occurrence + qualitative aspect of it)

39
Q

Time sampling vs. event sampling

A

Time Sampling: selection of time periods during which observations will occur (ex. every 20 seconds at 2 min intervals)

Event Sampling: selection of integral behaviors/events to observe, more for infrequent events

40
Q

Biophysiologic Measures

A

–> used for wide variety of purposes: basic biophysiologic processes, exploring ways in which nursing actions/interventions affect physiologic outcomes, product assessments, etc

In Vivo: performed directly within or on living organisms (ex. BP, temp)

In Vitro: gathered b extracting biophysiologic material from them and analyzing it (ex. hormone levels, bacterial counts, tissue biopsies)

41
Q

Advantages of Biophysiologic Measures

A
  • relatively accurate/precise
  • objective (two nurses would read same BP on monitor/two monitors would read the same)
  • pts cannot easily distort measurements
  • provide valid measures of targeted measures (thermometers measure temperature, not blood volume)
42
Q

Semantic Differential Scale

A

• Continuum between 2 adjectives
• Continuum varies from 5 to 9
Ex. My nurse is..
MEAN ——————-NICE

Research (10 decks)

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