This document discusses errors in research design, specifically non-sampling errors. It defines non-sampling error as error due to factors other than random sampling. Some potential sources of non-sampling error mentioned include surrogate information error, measurement error, population definition error, sampling frame error, data analysis error, respondent selection error, questioning error, recording error, and cheating error. The document also discusses non-response error and response error as specific types of non-sampling errors and provides examples of sources of non-sampling errors like inadequate data specification and errors in data collection, tabulation, and presentation.

1. Errors in research design
Dr. Ramadan Gharbia
Delta university

2. After reading you will be able to know
1-Errors in Marketing Research.
2- WHAT IS NON-SAMPLING ERROR.
3- SOURCES OF NON-SAMPLING ERRORS.

3. Potential Sources of Error in Research Designs
Surrogate Information Error
Measurement Error
Population Definition Error
Sampling Frame Error
Data Analysis Error
Respondent Selection Error
Questioning Error
Recording Error
Cheating Error
Inability Error
Unwillingness Error
Total Error
Non-sampling
Error
Random Sampling
Error
Non-response
Error
Response
Error
Interviewer Error Respondent
Error
Researcher
Error

4. Errors in Marketing Research
 The total error :
 is the variation between the true mean value in the population of the
variable of interest and the observed mean value obtained in the
marketing research project.
 Random sampling error :
 is the variation between the true mean value for the population and
the true mean value for the original sample.

5. Errors in Marketing Research
 Non-sampling errors:
 can be attributed to sources other than sampling, and they may be
random or nonrandom:
 including errors in problem definition, approach, scales,
questionnaire design, interviewing methods, and data preparation
and analysis.

6. Errors in Marketing Research
 Non-response error arises when some of the respondents
included in the sample do not respond.
 Response error arises when respondents give inaccurate
answers or their answers are mis recorded or mis analyzed.

7. WHAT IS NON-SAMPLING ERROR
- Non sampling error is such which are due to the
factors other than sampling are called non –
sampling errors.

8. SOURCES OF NON-SAMPLING ERRORS
 Lack of proper specification of the domain of study and
scope of investigation,
 Incomplete coverage of the population or sample(inability
to respond/Refusal to respond/inability to contact)
 Defective methods of data collection and Tabulation
errors(Researcher effect).

9. Other Reasons
- The data specification may be inadequate and inconsistent with the
objectives of the survey or census.
- Due to imprecise definition of the boundaries of area units, incomplete or
wrong identification of units,
- faulty methods of enumeration etc, the data may be duplicated or may be
omitted.

10. CONTINUE….
The scrutiny of data is not adequate.
The coding, tabulation etc. of the data may be erroneous.
There can be errors in presenting and printing the tabulated
results, graphs etc.
In a sample survey, the non-sampling errors arise due to
defective frames and faulty selection of sampling units.

11. THANK YOU
Thank you all and
best of luck