Depending upon the sources utilized, whether the data has come from actual observations or from records that are kept for normal purposes, statistical data can be classified into two categories, primary and secondary
Primary data is one, which is collected by the investigator himself for the purpose of a specific inquiry or study. Such data is original in character and is generated by surveys conducted by individuals or research institutions.
Some common types of primary data are:
- Demographic and socioeconomic characteristics
- Psychological and lifestyle characteristics
- Attitudes and opinions
- Awareness and knowledge: for example, brand awareness
- Intentions: for example, purchase intentions. While useful, intentions are not a reliable indication of actual future behavior.
- Motivation: a person’s motives are more stable than his/her behavior, so motive is a better predictor of future behavior than is past behavior.
Primary data can be obtained by:
Involves questioning respondents either verbally or in writing. This method is versatile, since you need only to ask for the information; however, the response may not be accurate. Communication usually is quicker and cheaper than observation.
Involves the recording of actions and is performed by either a person or some mechanical or electronic device. Observation is less versatile than communication since some attributes of a person may not be readily observable, such as attitudes, awareness, knowledge, intentions, and motivation. Observation also might take longer since observers may have to wait for appropriate events to occur, though observation using scanner data might be quicker and more cost effective. Observation typically is more accurate than communication.
Have an interviewer bias that mail-in questionnaires do not have. For example, in a personal interview the respondent’s perception of the interviewer may affect the responses.
The questionnaire is an important tool for gathering primary data. Poorly constructed questions can result in large errors and invalidate the research data, so significant effort should be put into the Questionnaire
When an investigator uses the data, which has already been collected by others, such data is called secondary data. This data is primary data for the agency that collects it and becomes secondary data for someone else who uses this data for his own purposes. The secondary data can be obtained from journals, reports, government publications, publication of professional and research organization and so on. For example, if a researcher desires to analyze the weather conditions of different regions, he can get the required information or data from the records of the meteorology department.
There are several criteria that you should use to evaluate secondary data.
- Whether the data is useful in the research study.
- How current the data is and whether it applies to time period of interest.
- Errors and accuracy – whether the data is dependable and can be verified.
- Presence of bias in the data.
- Specifications and methodologies used, including data collection method, response rate, quality and analysis of the data, sample size and sampling technique, and questionnaire design.
- Objective of the original data collection.
- Nature of the data, including definition of variables, units of measure, categories used, and relationships examined.