Method Of Data Collection Flashcards
In collecting the data, the researcher must decide:
Which data to collect—– variable
How to collect the data —— measurement tool
Who will collect the data—- expert vs non-expert
When to collect the data
Selection of data collection method should be based on the
The identified hypothesis or research problem
The research design
The information gathered about the variables
Described as a device used to collect data.
Instrument or a Tool
Facilitate variable observation and measurement.
Instrument or a Tool
The type of instrument used by the researcher depends on
the data collection method selected.
Most commonly used measurement tool in research
Questionnaire
The instrument (tool) used to collect data should be
مجموعة في قولنا
“Smart Instruments Verify Reliable Content Always”
• Smart: Suitable for its function.
• Instruments: Include an item that directly asks the hypothesis.
• Verify: Valid and reliable (free of bias).
• Reliable: Relevant content to test the hypothesis or answer the question.
• Content: Clue-free (free of built-in clues).
• Always: Ensures these characteristics are maintained.
Validity is Reliability and العكس غير صحيح . True / False
True
Data collection techniques and tools may by
Observation
Questionnaire
Interviews
Focus group sessions
A series of questions designed to elicit information, which is filled in by all participants in the sample.
Questionnaire
Advantages of Questionnaire
Relatively simple method of obtaining data.
Less time is consumed.
Researcher is able to gather data from a widely scattered sample.
The most common type of research instrument
Questionnaire
Disadvantages of questionnaires
Responses to a questionnaire lack depth.
Respondent may omit or disregard any item he chooses.
Some items may force the subject to select responses that are not his actual choice.
Length of the questionnaire is limited according to the respondent’s interest.
Data are limited to the information that is voluntarily supplied by the respondents.
Some items may be misunderstood.
The sample is limited to those who are literate.
A series of questions designed to elicit information, which is filled in by all participants in the sample
Questionnaire
Questionnaire can be gathered either by
oral interview or by written questionnaire
The type of questionnaire in which it is most common in research
Closed-ended questions:
It asks respondents to choose from two or more preselected answers
Closed-ended questions
Advantages of closed ended type of questionnaire
Advantages:
They are quicker and easier to answer
The answers are easier to tabulate and analyze
The list of possible answers often helps clarify the meaning of the question
Disadvantages of closed ended type of questionnaire
١- توجه المشترك نحو الإجابة ، بعطي اجابات غير دقيقة. ٢- الخيارات غير شاملة لذلك يجب وضع خيار اخير ( أخرى … )
The respondents answers in their own words
Open-Ended Questions
Advantages of open ended type of questionnaire
Leave the respondent free to answer with fewer limits imposed by the researcher.
Allow participants to report more information.
Disadvantages of open ended questionnaire
Difficulty in analysing data (Require coding system)
Phrases and words used by respondents require subjective judgments
The participant is asked to mark on a continuum from one extreme to the other, that best represents his characteristic
The visual analogue scale (VAS)
Types of questionnaires
Closed ended type
Open ended type
The visual analogue scale VAS
Directing the respondent to the next appropriate question
Branching question
Personal interview are necessary:
If the study requires direct observation of participants
Requires physical examination
People who don’t have telephones..etc
Participants are Elderly and /or ill persons.
Advantages and disadvantages of interview
Better for collecting answers to complicated questions that require
explanation or guidance.
It can make sure that responses are complete.
They are more costly and time consuming
Reliability = ………
Precision
……… = accuracy
Validity
How close are the measurements to
the true value.
Validity
How reproducible are measurements?
Reliability
measure what is intended to be measured.
Validity
someone else using the same method in the same
circumstances should be able to obtain the same findings (your findings are repeatable).
Reliability
To clarify, refine, and time the questionnaire
To find out whether each question produces an adequate range of responses.
Pre-test
Possible sources of bias during data collection:
Defective instruments
Observer bias
Missing information
Recall bias
Main sources of inaccuracy
Observer
Subject
Instrument
Strategies for Enhancing Accuracy
- Standardizing the measurement methods:
- Training and certifying the observers:
- Refining the instruments.
- Automating the instruments
- Calibrating the instrument : (Consistently high BP readings due to manometer being
out of adjustment Calibrate each month) - Blinding:
Observer: (Conscious or unconscious tendency for observer to read BP lower in
active treatment group Use double-blind placebo)
Subject : Tendency of subject to over report side effects if she knew she was on active
drug Use double-blind placebo
Strategies for Enhancing Precision
- Standardizing the measurement methods:
Preparing study protocols and Preparing operations manual
Writing specific guidelines or instructions for making each measurement - Training and certifying the observers:
Test of the mastery of the techniques to certify that observers have achieved the
prescribed level of performance. - Refining the instruments.
Writing or spelling out questionnaires and interviews to increase clarity - Automating the instruments: Reducing variations of human observers
measurements can be achieved by:
Automatic mechanical devices (electronic BP)
Self-response questionnaires - Repetition: Random error is reduced by repeating the measurement, and using the
mean of the two or more readings
(The problem is the added cost and practical difficulties of repeating the measurements
Pilot studies may also have a number of limitations.
The possibility of making inaccurate predictions or assumptions on the basis of pilot data;
A further concern is that of contamination.
