Sources, Acquisition, and Classification of Data
- Primary data — collected first-hand by the researcher (surveys, experiments, observation).
- Secondary data — already collected and published by someone else (government reports, published statistics).
- Classification can be by attribute (qualitative characteristic) or by variable (quantitative, measurable characteristic), and further arranged as a simple, one-way, two-way, or manifold classification depending on how many characteristics are considered together.
Quantitative and Qualitative Data
| Quantitative data | Qualitative data |
|---|---|
| Numerical, measurable (marks, age, income) | Descriptive, categorical (gender, opinion, colour) |
| Analysed using statistical measures — mean, median, standard deviation | Analysed by categorisation, thematic coding, and description |
Graphical Representation and Mapping of Data
| Chart type | Best used for |
|---|---|
| Bar chart | Comparing discrete categories |
| Histogram | Showing frequency distribution of continuous data |
| Pie chart | Showing proportion of a whole |
| Table chart | Presenting exact figures across multiple categories |
| Line chart | Showing a trend over time |
Data Interpretation
Typical NET questions give a table, bar chart, pie chart, or line graph and ask the candidate to calculate percentages, ratios, averages, or percentage change across categories. The key skill is reading axis labels and units correctly and choosing the shortest arithmetic route (e.g., converting to a common base before comparing).
Data and Governance
Reliable data underlies evidence-based policy-making, budgeting, and monitoring of government schemes. Open Government Data platforms, census and NSSO surveys, and administrative data systems increasingly support transparent and accountable governance, though issues of data privacy and data quality remain central concerns.