Methods of collecting primary and secondary data.

In Statistics, the data collection is a process of gathering information from all the relevant sources to find a solution to the research problem. It helps to evaluate the outcome of the problem.

Most of the organization uses data collection methods to make assumptions about future probabilities and trends. Once the data is collected, it is necessary to underdo the data organization process.

The data collection method is divided into two categories namely,

• Primary Data Collection methods
• Secondary Data Collection methods

let us discuss the different types of data collection methods and their advantages and limitations

1. Primary Data Collection Methods

Primary data or raw data is a type of information that is obtained directly from the first-hand source through experiments, surveys, or observations. The primary data collection method is further classified into two types. They are

• Quantitative Data Collection Methods
• Qualitative Data Collection Methods

Quantitative Data Collection Methods

It is based on mathematical calculations using various formats like close-ended questions,Correlation and regression methods, mean, median or mode methods. This method is cheaper than qualitative data collection methods, and it can be applied in a short duration of time.

Qualitative Data Collection Methods

It does not involve any mathematical calculations. This method is closely associated with elements that are not quantifiable. This qualitative data collection method includes interviews, questionnaires, observations, case studies etc. 

There are several methods to collect primary data. They are

1.    Observation Method

Observation method is used when the study relates to behavioural science. This method is planned systematically. It subjects many controls and checks. The different types of observations are:

(a)   Structured and unstructured observation: when a is characterized by careful definition of units to be observed, style of observer, conditions for observation and selection of pertinent data of observation it is a structured observation. When there characteristics are not thought of in advance or not present it is a structured observation.

(b)   Controlled(laboratory) and uncontrolled(exploratory) observation: If the observation takes place in the natural setting it is a uncontrolled observation but when observer takes place according to some pre-arranged plans, involving experimental procedure it is a controlled observation.

(c)   Participant, non-participant and disguised observation.

Ø  Advantages:

·         Subjective bias is eliminated

·         Data is not affected by past behaviour or future intentions

·         Natural behaviour of the group can be recorded

Ø  Limitations:

·         Expensive methodology

·         Information provided is limited

·         Unforeseen factors may interfere with the observational task.

2.    Interview Method:

The method of collecting data in terms of oral or verbal responses. It is achieved in two ways, such as

(A)    Personal Interview – In this method, a person known as an interviewer is required to ask questions face to face to the other person. The personal interview can be-

·         Direct personal investigation- The interviewer has to collect the information personally from the service concerned.

·         Indirect oral examination- The interviewer has to cross examine other persons who are suppose to have a knowledge about the problem.

·         Structured Interviews-Interviews involving the use of pre-determined questions and of highly standard techniques of recording.

·         Unstructured Interviews: It does not fallow a system of pre-determined questions and is characterized by flexibility of approach to questioning.

·         Focused interview-  It is meant to focus attention on the given experience of the respondent and its effect. The interviewer may ask  questions in any manner or sequence with the aim to explore reason and motives of the respondent.

·         Clinical interviews- It is concerned with broad underlying feeling and motives or individuals life experience which are used as method to ellict information under this method at the interviewer direction.

·         Non directive interview-The interviewers function is to encourage the respondent to talk about the given topic with the a bare minimum of direct questioning.

Advantages-

·         More information and in depth can be obtained

·         Samples can be controlled

·         There is greater flexibility under this method

·         Personal information can as well be obtained

 Limitations

      ·         It is an expensive method.

      ·         Possibility of bias interviewer or respondent.

      ·         More time consuming.

      ·         Possibility of imaginary info and less frank responses.

      ·         High skilled interviewer is required.

(B)   Telephonic Interview – In this method, an interviewer obtains information by contacting people on the telephone to ask the questions or views orally.

  Ø  Adventages-

·         It is fast , flexible and cheaper than other methods.

·         Recall is easy and there is a higher rate of response.

·         No field staff is required.

  Ø  Limitations-

·         Interview period exceed five minutes maximum which is less.

·         Questions have to be short and to the point.

·         Less information can be collected

3.    Questionnaire Method:

In this method, the set of questions are mailed to the respondent. They should read, reply and subsequently return the questionnaire. The questions are printed on the definite order on the form. A good survey should have the following things:

• Short and simple
• Should follow a logical sequence
• Provide adequate space for answers
• Avoid technical terms
• Should have good physical appearance such as colour, quality of the paper to attract the attention of the respondent

Ø  Adventages-

·         Free from bias of interviewer

·         Respondents have adequate time to give answers

·         Respondents are easily and conveniently approachable

·         Large samples to be used to be more reliable

Ø  Limitations-

·         Low rate of return of duly filled Questionnaire

·         It is inflexible once sent

·         Time taking and slow process

4.    Schedules:

       This method is similar to the questionnaire method with a slight difference. The enumerations are specially appointed for the purpose of filling the schedules. It explains the aims and objects of the investigation and may remove misunderstandings if any have come up. Enumerations should be trained to perform their job with hard work and patience.

2. Secondary Data Collection Methods

Secondary data is data collected by someone other than the actual user. It means that the information is already available, and someone analyses it. The secondary data includes magazines, newspapers, books, journals etc. It may be either published data or unpublished data.

Published data are available in various resources including

• Government publications
• Public records
• Historical and statistical documents
• Business documents
• Technical and trade journals

Unpublished data includes

• Diaries
• Letters
• Unpublished biographies  or works etc.

Before using secondary data, it must be checked for the following characteristics-

  1.    Reliability of data: Certain Questions to be checked

 Who collected the data?

 From what source?

 Which method?

 Time?

 Possibility of bias?

 Accuracy?

   2.    Suitability of data: The object, scope and nature of the original enquiry must be studies and then carefully scrutinize the data for suitability.

   3.    Adequacy: The data is considered inadequate if the level of accuracy achieved in data is found inadequate or if they related to an area which may be either narrower or wider than the area of the present enquiry.

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   A. R Statistics