by Planning of a Statistical Enquiry refers to the systematic preparation made before collecting and analysing data. It determines what information is required, why it is required, from whom it will be collected, how it will be collected, and how it will be analysed. Proper planning ensures that the enquiry is conducted efficiently and produces reliable results. It helps avoid unnecessary expenditure, wastage of time, incomplete information, and errors during the investigation.
Steps in Planning a Statistical Enquiry
Step 1. Defining the Problem
The first step in planning a statistical enquiry is to clearly define the problem to be studied. The investigator must understand the nature of the problem, its background, and the specific questions requiring answers. A clearly defined problem prevents the collection of unnecessary information and keeps the enquiry focused. For example, a business may investigate declining sales, customer satisfaction, or employee turnover. Proper problem definition provides a clear direction for the entire investigation and helps determine the type of data required.
Step 2. Determining the Objectives
After defining the problem, the investigator should establish clear objectives of the enquiry. Objectives specify what the investigation intends to discover, measure, compare, or evaluate. They should be specific, practical, and directly related to the problem. For example, an enquiry may aim to measure customer preferences or determine changes in sales over several years. Clearly stated objectives guide data collection, analysis, and interpretation and help determine whether the enquiry has successfully achieved its intended purpose.
Step 3. Determining the Scope of Enquiry
The scope of enquiry defines the boundaries within which the investigation will be conducted. It includes the population, geographical area, time period, subject matter, and units of study. For example, an enquiry may cover customers of a particular city during one financial year. Clearly determining the scope prevents unnecessary expansion of the investigation and helps control time, cost, and resources. A well-defined scope also ensures that the collected information remains relevant to the objectives.
Step 4. Determining the Sources of Data
The investigator must decide the appropriate sources of data before beginning the enquiry. Data may be obtained from primary sources or secondary sources. Primary data are collected directly from respondents through surveys, interviews, observation, or experiments. Secondary data are obtained from existing records, government publications, company reports, books, and databases. The choice depends on the purpose, availability, accuracy, and cost of information. Selecting suitable sources helps ensure that the enquiry is based on relevant and reliable data.
Step 5. Selecting the Method of Data Collection
The next step is selecting a suitable method of data collection. Common methods include direct personal investigation, interviews, questionnaires, schedules, observation, and experimentation. The method should be selected according to the nature of the study, characteristics of respondents, available resources, and required accuracy. A properly selected method improves the quality of collected information and reduces errors. The investigator should also consider time, cost, accessibility, and respondent cooperation before finalizing the data collection method.
Step 6. Deciding Census or Sampling
The investigator must decide whether the enquiry will use a census method or a sampling method. Under the census method, information is collected from every unit of the population. Under sampling, only a selected representative portion is studied. Census may provide comprehensive information but usually requires greater time and cost. Sampling is economical and faster but requires careful selection of representative units. The decision should depend on population size, resources, accuracy requirements, and nature of the investigation.
Step 7. Preparing the Investigation Plan
A detailed investigation plan should be prepared before actual fieldwork begins. It specifies the procedures, responsibilities, resources, time schedule, and methods to be followed. The plan may include preparation of questionnaires, selection and training of investigators, field arrangements, supervision, and methods of checking collected information. Proper planning ensures coordination and systematic execution of the enquiry. It also helps identify possible difficulties in advance and provides suitable solutions, thereby reducing delays and unnecessary expenditure.
Step 8. Deciding the Method of Analysis
The final planning step is to determine the appropriate method of data analysis. The investigator should decide in advance which statistical techniques will be used to process and interpret the collected information. Depending on the objectives, methods such as averages, percentages, measures of dispersion, correlation, regression, and index numbers may be applied. Planning analysis beforehand ensures that the collected data are suitable for statistical treatment. It ultimately helps produce meaningful conclusions and reliable decisions.
