Training Course on Basic Statistics for Research August 24-28, 2009 STATISTICAL RESEARCH AND...

Training Course on Basic Statistics for Research

August 24-28, 2009

STATISTICAL RESEARCH AND TRAINING CENTERJ and S Building, 104 Kalayaan Avenue, Diliman, Quezon City

Methods of Data Collection

Prepared by: Prof. Josefina V. Almeda

School of StatisticsUP Diliman

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Statistical Research and Training Center Training Course on Basic Statistics for ResearchAugust 24 - 28, 2009

Survey method

Observation method

Use of existing records

Experimental method

Registration

Data Collection Methods

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Survey

• used to collect quantitative information about items in a population or a sample.

• Surveys of human populations and institutions are common in political polling and government, health, social science and marketing research.

• A survey may focus on opinions or factual information depending on its purpose, and many surveys involve administering questions to individuals.

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Serial Surveys

are those which repeat the same questions at different points in time, producing time-series data. They typically fall into two types:

Cross-sectional surveys which draw a new sample each time. In a sense any one-off survey will also be cross-sectional.

Longitudinal surveys where the sample from the initial survey is recontacted at a later date to be asked the same questions.

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Examples of Surveys

The Social Weather Station does a quarterly survey on families regarding unemployment, quality of life, and work status. The respondents are selected adults from the population.

Pulse Asia conducts sample surveys on voter response to political ads. The respondents are selected registered voters who intend to vote in the next elections.

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Advantages of Surveys

It is an efficient way of collecting information from a large number of respondents.

Surveys are flexible in the sense that a wide range of information can be collected. They can be used to study attitudes, values, beliefs, and past behaviors.

There is an economy in data collection due to the focus provided by standardized questions. Only questions of interest to the researcher are asked, recorded, codified, and analyzed. Time and money is not spent on tangential questions.

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Disadvantages of Surveys

They depend on subjects’ motivation, honesty, memory, and ability to respond.

They may not be motivated to give accurate answers, in fact, they may be motivated to give answers that present themselves in a favorable light.

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Methods of Communication in Doing Surveys

personal interview mail telephone focused group discussion (FGD) online surveys Self-administered questionnaire

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Personal Interview

Fewer misunderstood questions and inappropriate responses.

Fewer incomplete responses.

Generally higher response rate.

Respondents may be unwilling to discuss sensitive topics with a stranger.

Additional information can be collected from respondent.

Subject to interviewer bias (e.g. answers influenced by desire to impress interviewer).

Generally expensive/time-consuming to run.

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Mailed Questionnaire

the questionnaire may be handed to the respondents or mailed to them, but in all cases they are returned to the researcher via mail.

cost is very low, since bulk postage is cheap in most countries

long time delays, often several months, before the surveys are returned and statistical analysis can begin

not suitable for issues that may require clarification respondents can answer at their own convenience

(allowing them to break up long surveys; also useful if they need to check records to answer a question)

no interviewer bias introduced

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Telephone Surveys

use of interviewers encourages sample persons to respond, leading to higher response rates

interviewers can increase comprehension of questions by answering respondents' questions.

fairly cost efficient, depending on local call charge structure

some potential for interviewer bias (e.g. some people may be more willing to discuss a sensitive issue with a female interviewer than with a male one)

cannot be used for non-audio information (graphics, demonstrations, taste/smell samples)

unreliable for consumer surveys in rural areas where telephone penetration is low

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Focused Group Discussion

A moderator follows an interview guide to direct a freewheeling discussion among a small group of homogeneous people

Qualitative type of data collection

Verbatim

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Online Surveys

can use web or e-mail web is preferred over e-mail because interactive HTML

forms can be used often inexpensive to administer very fast results easy to modify if not password-protected, easy to manipulate by

completing multiple times to skew results data creation, manipulation and reporting can be

automated data sets created in real time

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Self-Administered Questionnaire

Respondents are more likely to stop participating mid-way through the survey (drop-offs).

Respondents cannot ask for clarification.

Low response rate in some modes.

Allows shy respondents to answer sensitive questions in private.

No interviewer intervention available for probing or explanation.

Respondents can read the whole questionnaire before answering any questions.

Free of interviewer bias.

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Personal Mall Intercept Survey

shoppers at malls are intercepted - they are either interviewed on the spot, taken to a room and interviewed, or taken to a room and given a self-administered questionnaire

socially acceptable - people feel that a mall is a more appropriate place to do research than their home

potential for interviewer bias

fast

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Methods used to increase response rates

brevity - single page if possible financial incentives non-monetary incentives

• commodity giveaways (pens, notepads) • entry into a lottery, draw or contest • discount coupons • promise of contribution to charity

preliminary notification claimed affiliation with universities, research institutions, or charities emotional appeals bids for sympathy convince respondent that they can make a difference guarantee anonymity legal compulsion (certain government-run surveys)

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Interviewer’s Task

• To locate the sample respondents

• To obtain the interviews with them and to ask the

questions and record the answers as instructed.

• To make call backs if the respondent is not around or

not available during the time of interview.

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Asking the Questions

• In most large-scale surveys, the aim is to attain uniformity

in the asking of questions and recording of answers.

• The training of interviewers is oriented towards efficiency in

following instructions.

• A manual for interviewers is prepared which provides the

instructions on how to ask questions, the meaning of terms

and how to solve some problems that may be encountered in

the course of their interviewing respondents.

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Characteristics of Field Interviewers

An interviewer should be

• pleasant

• tactful

• reliable

• honest

• patient

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Selection of Field Enumerators

• passes the IQ test

• good handwriting

• age limit

• physically able

• willing to work beyond office hours

• preference is given to college graduates although the general

requirement is at least two years in college.

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Some Sources of Response Errors

(a) Interviewers’ bias

(b) Respondents’ bias

(c) Question wording

(d) Question order

(e) Question structure

(f) Length of Questionnaire

(g) Coding

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Use of Documented Data

a mass of information about the populations or samples studied by statistical surveys is available in historical documents, statistical reports, records of institutions and other sources

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Examples of Sources of Documented Data

The Department of Health is responsible for health statistics like infant deaths, maternal deaths, malnutrition, etc.

The National Statistical Coordination Board compiles data necessary from different government agencies and computes for gross national product, gross domestic product, and consumer price index.

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Classification of Documented Data by Source

Primary Data

data documented by the data collectors’ themselves

Secondary Data

data documented by other individuals or agencies

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Observation

• Observation can fairly be called the classic method

of scientific inquiry.

• The accumulated knowledge of biologists,

physicists, astronomers and other natural scientists

is built upon centuries of systematic observation,

much of it of phenomena in their natural

surroundings rather than in the laboratory.

• Makes possible the recording of the behavior but only at the

time of occurrence

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Types of Observation

Unstructured Observation

Observer joins the group or detaches from the group

Structured Observation

Observer makes use of formal instruments and makes a specific plan before data collection is done in a field or laboratory

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Experimental Method

There is actual human interference with the conditions controlling the environment

Collecting the data under controlled conditions

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Registration

Data that are registered to comply with certain laws, ordinances, or standard practices

It is a practical and inexpensive method of getting facts.

Training Course on Basic Statistics for Research

August 24-28, 2009

STATISTICAL RESEARCH AND TRAINING CENTERJ and S Building, 104 Kalayaan Avenue, Diliman, Quezon City

Thank you.

Training Course on Basic Statistics for Research August 24-28, 2009 STATISTICAL RESEARCH AND...

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