Personal, Telephone and Mail Interviews

Methods of Data Collection

Personal Interview

Characterized by interaction of Four

Entities:

Researcher

Interviewer

Interviewee

Interview Environment

Personal Interview Methods Door to Door Interviewing

Executive Interviewing

Mall Intercept Surveys

Self-Administered Interviews

Purchase Intercept Technique (PIT)

Omnibus Surveys

Personal Interviews (Advantages)

Can arouse and keep interest Can build rapport Ask complex questions with the help

of visual and other aids Clarify misunderstandings High degree of flexibility Probe for more complete answers

Personal Interviews (Advantages) Good for neutral questions Do not need an explicit or current list

of households or individuals

Personal Interviews (Limitations) Bias of Interviewer

Response Bias

Embarrassing/personal questions

Time Requirements

Cost Per Completed Interview Is High

Trained staff of interviewers

geographically near the sample required

Telephone Interviewing

Selecting telephone numbers1. Pre-specified list

2. A directory

Random dialing procedure1. Random digit dialing

2. Systematic random digit dialing (SRDD)

3. Plus-one dialing

Telephone Interviewing (Advantages)

Central location, under supervision, at own hours

More interviews can be conducted in a given time

Travelling time is saved

Shorter data collection periods

More hours of the day are productive

Telephone Interviewing (Advantages)

Repeated call backs at lower cost (WATS)

Absence of administrative costs

Lower cost per completed interview

Less sample bias due to no response

Intrusiveness of the phone

Ease of call backs

Telephone Interviewing (Limitations)

Inability to employ visual aids or complex

tasks

Interviewer must rely solely on verbal cues

to judge the reaction and understanding of

respondents

Can't be longer than 5-10 min. or they get

boring

Telephone Interviewing (Limitations)

Amount of data that can be collected

is relatively less

A capable interviewer essential

Potential for sample bias

No phone, unlisted phone or mobile

phones

Mail Surveys

Requires a broad identification of the

individuals to be sampled before data

collection begins

Some Decisions That Need to Be Taken

Are: Type of Return Envelope Postage Method of Addressing

Mail Surveys

Cover Letter The Questionnaire Length, Layout,

Color, Format etc Method of Notification Incentive to Be Given

Mail Surveys (Advantages) Lower cost

Better results, including a shorter response time

Reliable answers as no inhibiting intermediary

Survey answered at respondents’ discretion

Mail Surveys (Advantages) Can be accomplished with minimal staff

and facilities. Provides access to widely dispersed

samples. Respondents have time to give

thoughtful answers, look up records, or

consult others.

Mail Surveys (Limitations)

The identity of the respondent is

inadequately controlled

No control over whom the respondent

consults before answering the questions

The speed of the response can't be

monitored

No control on the order in which the

questions are exposed and answered

Mail Surveys (Limitations) Respondents’ understanding of the questions

The respondent may not clearly

understand the question and has no

opportunity to clarify

Cannot have long questionnaires

Subject to availability of a mailing list

Response rate is generally poor

Mail Surveys (Limitations) Number of problems such as

obsolescence, omissions, duplications,

etc

Drop-off Questionnaire (Advantages)

The interviewer can explain the study,

answer questions, and designate a

respondent. Response rates tend to be like those of

personal interview studies. There is more opportunity to give

thoughtful answers and consult records.

Drop-off Questionnaire (Disadvantages)

Costs about as

much as personal

interviews. A field staff is

required.