Data Collection Bakr M. Bin Sadiq Pediatric Specialist Senior Clinical and Field Epidemiologist Certified in International Research Ethics

Objectives Kinds of data collection tools and techniques The benefits of using a combination of different data collection techniques Sources of bias in data collection, and ways to prevent bias

Where to start! Before designing a method of data collection, the researcher should write: Detailed information on the subject of data to be collected. Concepts to be measured in the study

Selecting Study Variables Define the keywords contained in the research questions Operationalize these keywords Concept Indicator Income Monthly net salary GP workload Number of patients seen Referral rate Patients sent to outpatients Elderly Aged over 65

Data Collection Techniques vs. Data Collection Tools Record Sources Checklist, formats Observing Eyes, pen/paper, watch, scale, microscope, checklist Interviewing Interview schedule, checklist, tape recorder Focus group discussion FGD guide, tape recorder Written questionnaire Questionnaire

Data Collection Techniques Recorded Sources Observation Interview Focus group discussion Written questionnaire

Recorded Sources A data collection technique that involves locating and analyzing information that has already been collected (old data) Advantage Not expensive Permits examination of trends over the past Disadvantage Difficulty in gaining access (privacy) Information recorded may be biased

Observation Observation is a technique which involves systematically selecting, watching and recording behavior and characteristics of living beings, objects or phenomena.

Observation Advantage Disadvantage Give more detailed information Allow to collect information on facts not mentioned in the questionnaire Allow to test reliability of responses to questionnaire Disadvantage Observation bias Presence of researcher can influence the situation

Interview An interview is a data collection technique that involves oral questioning of respondents, either individually or as a group

Interview Advantage Disadvantage Suitable for illiterates Clarification of questions is possible Higher response rate Disadvantage Presence of researcher can influence responses Records of events may be less complete than with observations

Focused group discussion A focused group discussion consists of a group discussion in which a small number of participants (usually 6 to 12 ) of similar status under the guidance of a moderator and with at least one additional observer talk about topics of relevance to particular study.

Focused group discussion Advantage Provides in-depth qualitative information Disadvantage Shy participants Domineering participants

Written questionnaire A written questionnaire (self-administered) is a data collection technique in which written questions are presented that are to be answered in written form by the respondents themselves.

Written questionnaire Advantage No need of research assistant to administer it No bias in asking the questions differently More honest responses Disadvantage Not possible to use illiterate respondents Low rate of response Questions may be misunderstood

Importance of Techniques Combination They complement each other Maximizes the quality Reduces the chances for bias

Bias in Information Collected A bias is distortion in the data collected such that the information is no longer representative of the true situation

Sources of Bias Defective instruments, such as: pre-coded questionnaire – not enough is known about the topic semi-structured questionnaire – no guidelines on how to ask or answer weighing scales – not standardized

Sources of Bias Observer bias researcher will only see or hear things in which he is interested it’s preferable to have two persons information has to be recorded and discussed immediately

Sources of Bias Effects of interviewer on informant informant may mistrust the intention of the researcher – give misleading answers

Written Questionnaire Design

Construction of a questionnaire A title should be short and clear. An address. An identifier Instructions: tell about the study and how to complete the questionnaire. The layout: the questionnaire should appear neat, and attractive

Construction of a questionnaire The ending: it is useful to offer a very open question right at the end. Example: Do you have any further points to make about this questionnaire? Thank you for helping with this study. Testing for problems.

Wording The objective should be construct questions that are: Simple. Free of ambiguity. Encourage accurate and honest responses without embarrassing or offending the respondent.

Clarity Questions must be clear and specific as possible. Example: How much exercise do you usually get? During a typical week, how many hours do you spend exercising?

Simplicity Questions should use simple, common words that convey the idea and avoid technical terms. Example: “Drugs you can buy without a doctor’s prescription” “Over-the-counter medications”.

Neutrality Avoid words that suggest that there is a most desirable answer. Example: During the last month, how often did you smoke too much cigarettes? During the last month, how often did you smoke more than five cigarettes in one day?

Types of questions There are two basic types of questions: Open-ended questions. Closed-ended questions.

Open-ended questions Open ended questions are particularly useful when it is important to hear what respondents have to say in their own words. Example: What habits do you believe increase a person’s chance of having a heart attack? ________________________________________________________________________________________________________

Open-ended questions Advantages Useful for exploring new areas. Respondents can say their own words. Disadvantages Require qualitative methods to code and analyze the responses, which take time and subjective judgment.

Closed-ended questions Closed-ended questions are more common, these questions ask respondents to choose from one or more possible answers. Example: Which one of the following do you think increase a person’s chance of having a heart attack the most?(check one.) Smoking Being overweight Stress

Closed-ended questions Advantages: Quicker and easer to answer. Answers are easier to be analyze. Possible answers often help clarify the meaning of the question. Disadvantages: Lead respondents in certain directions. The possible answers may not include an answer that is most appropriate.

A structured (standardized) questionnaire A structured (standardized)questionnaire must be carefully set out and worded. Example: -Total family income per month in Saudi Riyals_____ -What is your height in meter?_____

A structured (standardized) questionnaire A self-administered questionnaire -Useful for straight forward information. -For large sample, cheap and quickly. An interview-administered questionnaire -Useful for complicated information. -Produces a higher response rate. -Better quality of information. -More time consuming and expensive.

Interviewing Methods Personal interviews Telephone surveys Mail Surveys Computer Direct Interviews Email Surveys Internet/Intranet (Web Page) Surveys

Summary Objective Speed Cost Your choice of data collection methods will depend on several factors: Objective Speed Cost