Sources of data

 

There are two sources of collecting the data

1.      Primary data

2.      Secondary data

 

Primary data are those which are collected for the first time and are thus original in character, whereas Secondary data are those that have already been collected by others and which ate usually available in journals, magazines or research publications. Primary data are in the shape of raw materials to which statistical methods are applied for the purpose of analysis and interpretation. Secondary data are usually in the shape of finished products since they have been treated statistically in some form or the other.

Factors affecting choice of method. It is obvious that the methods of the collection of primary data and secondary data would not be exactly identical because in one case the data have to be originally collected while in the other the work is of the nature of compilation. There are various methods of the collection of primary and secondary data and the choice of the method depends on a number of factors. Nature, object and scope of the enquiry are the most important things on which the selection of the method depends.

Availability of finance is another factor which influences the selection of the method of collection of data. When financial resources at the disposal of the investigator are scanty he shall have to leave aside expensive methods even though they are better than others which are comparatively cheap.

Availability of time has also to be taken into account. Some methods involve a long duration of enquiry while with others the enquiry can be conducted in a comparatively shorter duration. The time at the disposal of the investigator thus affects the selection of the technique by which data are to be collected.      

METHODS OF COLLECTING PRIMARY DATA

The following methods of the collection of primary data are in common use:-

(a) Direct personal investigation.

(b) Indirect oral investigation.

(c) By schedules and questionnaires.

(d) By local reports.       

(a) Direct personal investigation.

In direct personal investigation as the name suggests the investigator has to collect the information personally from the sources concerned. He has to be on the spot for conducting the enquiry and has to meet people from whom data have to be collected. It is necessary that in such cases the investigator has a keen sense of observation and he is very polite and courteous. In some cases it may not be possible or worthwhile to contact directly the persons concerned and in such cases the investigator has to cross-examine other persons who are closely in touch with the sources of data. The method of direct personal investigation is suitable only for intensive investigations. It involves enormous cost and usually requires a long time.

(b) Indirect oral investigation

When the above mentioned method cannot be used either on account of the unwillingness of persons to give information when approached directly, or on account of the extensive scope of the enquiry or on account of some other reason an indirect oral examination can be conducted. In this method data are not collected directly from the persons concerned but through indirect sources. Persons who are supposed to have knowledge about the problem under investigation are interrogated and the desired information is collected. Usually in such enquiries a small list of questions relating to the investigation is prepared and these questions are put to different persons (known as witnesses) and their answers are recorded. Most of the commissions and committees appointed by the Government to collect statistical data or to carry on such investigations in which true data have to be compiled, make use of this method.

 

(c) Schedules and questionnaires

An important method of the collection of data followed usually by private individuals, research workers, non-official institutions and sometimes the Government also, is that of schedules and questionnaires. In this method a list of questions relating to the problem under investigation is prepared and printed and information is collected from various sources in any of the following ways:-

(i)                 By sending the questionnaire to the persons concerned and requesting them to answer the questions and return toe questionnaire:

In order to have correct answers the investigator should be a very polite and further give them an assurance that if the informants so wish their replies would be kept confidential. Further the questions that are asked should be very carefully framed. The questions should be :- (1) Short and clear. (2) Easy to understand and answer. (3) Few in number. (4) Not such which call for a confidential information. (5) Not such which may hurt the sentiments of the informants.

However, this method cannot be used if the informants are illiterate.

 

(ii)               By sending the questionnaires through enumerators to help the informants in filling the answers:

In this method the enumerators go to the informants along with the questionnaires and help them in recording their answers. The enumerators explain the aims and objects of the investigation to the informants and also emphasise the necessity and usefulness of correct answers. They also remove the difficulties which any informant may feel in understanding the implications of a particular question or the definition or concept of difficult terms. This method is very useful in extensive enquiries and with it, fairly dependable results can he expected. It is, however, very expensive and usually such enquiries can be conducted only by the Government. Population census all Over the world is conducted by this method.

(d) By local reports

The last method of collection of primary data is through local reports. In this method data are not formally collected by enumerators but by the local correspondents or agents in their own fashion and to their own likings. Obviously such data cannot be very reliable and as such this method is used in those cases where the purpose of investigation can be served with rough estimates only and where a high degree of precision is not necessary. This method has the advantage of being least expensive.