The document describes different types of errors that can occur in survey research, including sampling error, systematic error, and measurement error. Sampling error can include only surveying a subset of the population that may not be fully representative. Systematic error includes issues with how the sample was selected, such as only surveying people listed in phone books. Measurement error involves inaccuracies that occur during data collection and processing, such as interviewer bias, poorly worded questions, incorrect data entry, and non-response bias where certain groups are less likely to participate. Addressing these various sources of error is important for conducting valid survey research.

1. Examples of Type of Errors in Survey Research
1) Sampling Error
• Random Sampling Error
Ex. If you want to study the attitudes of engineering students
regarding library services, it would not be enough to interview every
100th person who walked into the library. That technique would
only measure the attitudes of engineering students who use the
library, not those who do not. In addition, it would only measure the
attitudes of engineering students who happened to use the library
during the time you were collecting data. Therefore, the sample
would not be very representative of engineering students in general.
In order to be a truly representative sample, every student at
engineering would have to have had an equal chance of being chosen
to participate in the survey.
2) Systematic Error
Sample design Errors are the following:
• Frame Error
Ex. In conducting telephone interview, many households are not
listed in a current telephone book because they do not want to be
listed or are not listed accurately because they have recently
changed their telephone number regarding research about electricity
consumption during Christmas season.
• Population Specification Error
Ex. Error in the estimation of the amount of travel on 'employer’s
business' by personal vehicle, employer’s business' travel is defined
as travel on the business of the employer (e.g. trips to meetings, trips
between worksites etc), but excludes travel between home and work
(i.e. commuting).
• Selection Error
Ex. Door to door interviewers might decide to avoid houses that do
not look neat and tidy because they think the inhabitants will not be
agreeable to doing a survey. If people live in messy houses are
systematically different from those who live in tidy houses, then the
selection error will be introduced into the results of the survey.

2. 3) Measurement Error
• Surrogate Information Error
Ex. Kodak film was so popular in 80's. Their marketing line was
Kodak sells film, but they don't advertise film. They advertise
memories. It failed miserably in the marketplace when they suffered
bankruptcy in 2000's. People love taking pictures but because of the
rapid changes of technology they didn't survive because the real
question was never in the research which is, would they adapt those
changes to stay in the market.
• Interviewer Error
Ex. An interviewer conducted a street survey method and tries to
influence a respondent on answering the survey questionnaires in a
way respondent would be tempted to give untrue answers especially
when the interviewer was good looking and very convincing. Error
occurs when deliberate cheating takes place.
• Measurement Instrument Bias
Ex. Interviewer made open-ended questionnaires regarding brands
that Doctors usually prescribe to their patients. There is a bias on
questionnaire because it makes recording responses difficult and
prone to recording error since doctors he would ask might have
different preferences depending on their client's diseases.
• Processing Error
Ex. In evaluating UPHSL professors before the semester ends, student
might enter the wrong response to a particular professor which he
hates the most but was supposed to be intended to his favorite
professor. There was an error since the survey document to a
computer was transferred incorrectly.
• Nonresponse Bias
Ex. The marketing department of an airline made mail survey to their
passengers in every flight regarding their services and satisfaction.
Few months later, it proudly announced that it had a huge sample of
passenger's feedback. Therefore, it could only mean that potential
respondent is reached out but cannot or will not participate at that
time when airline posted that survey.
• Response Bias
Ex. The respondents may have a good idea of how many times they
visited a supermarket in the past month. However, they may not used
to buy in that particular supermarket rather in public market. Rather
than answering "No idea" in response to a question regarding which
supermarket they used to purchase goods, the respondents may
simply guess.