UPSC IES / ISS — 2025

• Official notification: 12 February 2025 (UPSC). :contentReference[oaicite:6]{index=6}
• Application window: As specified in the notification (online through UPSC portal). :contentReference[oaicite:7]{index=7}
• Written exam (2025): Held over 20–22 June 2025 (three days of papers). :contentReference[oaicite:8]{index=8}
• Vacancies (2025): Official vacancy table is in the notification PDF — check the vacancies section for IES & ISS counts. :contentReference[oaicite:9]{index=9}
• Selection process: Written examination (descriptive/objective depending on paper) → Personality Test (Interview). UPSC provides DAF & personality schedule after written results. :contentReference[oaicite:10]{index=10}

The Indian Economic Service (IES) and Indian Statistical Service (ISS) are specialist central services recruited through a competitive UPSC examination. IES officers are deployed in economic planning, policy and research roles across Government of India departments and ministries; ISS officers manage statistical systems, data collection, analysis and implementation of national surveys and statistical programmes.

These services require strong subject-matter expertise: economics (micro/macro/econometrics/public finance/Indian economics) for IES, and applied statistics (probability, sampling, inference, official statistics) for ISS. The UPSC notification and scheme provide full subject-wise scopes. :contentReference[oaicite:11]{index=11}

IES — Written Examination (Typical structure)

The IES written examination consists of multiple descriptive papers covering General English, General Studies and several economics papers (General Economics I, II, III and Indian Economics). Each paper carries specified marks and time (detailed in UPSC notification). See UPSC pdf for exact marks & paper names. :contentReference[oaicite:12]{index=12}

ISS — Written Examination (Typical structure)

ISS combines objective & descriptive papers focused on statistics and mathematics as applicable — General English/Studies may also be included per notification. Core papers include Statistics I–III covering probability, sampling, estimation, multivariate analysis, official statistics and survey methodology. Check the official syllabus in the UPSC PDF for full paper-wise lists. :contentReference[oaicite:13]{index=13}

Detailed paper names, marks and duration are as per the official UPSC notification and scheme PDF. Always use that PDF as the authoritative syllabus. :contentReference[oaicite:14]{index=14}

Eligibility conditions (educational qualifications, age limits and relaxations) and the number of vacancies for IES & ISS are published in the UPSC Notification. For IES, typically a postgraduate degree in Economics / Applied Economics / Econometrics / Business Economics is required; for ISS, a postgraduate degree in Statistics / Applied Statistics / Mathematical Statistics or related discipline is required — confirm exact phrasing in the official notice. :contentReference[oaicite:15]{index=15}

Vacancy summary (2025)

The official notification contains a vacancy table (check the Vacancies section of the PDF). Exam portals summarised the 2025 intake and gave the official totals — always confirm the exact category & post-wise split from the notification. :contentReference[oaicite:16]{index=16}

• Notification published: 12 Feb 2025 (UPSC). :contentReference[oaicite:17]{index=17}
• Application window: As specified in notification (apply via UPSC portal).
• Written examination: 20–22 June 2025 (three days of papers). :contentReference[oaicite:18]{index=18}
• DAF / Personality Test window: UPSC provides a 15-day DAF update window after written results for candidates qualified for Personality Test (see notification). :contentReference[oaicite:19]{index=19}

This plan assumes ~4–8 hours/day of focused study. Adjust according to baseline and working/studying constraints.

Weeks 1–4 — Foundation

• Map the full syllabus; create topic-wise notes. For IES focus on Micro/Macro fundamentals; for ISS build strong probability & sampling basics.
• Daily: 1 hour theory + 1 hour problem solving (economics/statistics) + 30 mins current affairs (policy/economy data).

Weeks 5–8 — Consolidation

• Begin timed sectional practice (2–3 hours sessions). Start solving previous-year mains questions (UPSC papers).
• Maintain an error log and concept checklist for recurring weak spots.

Weeks 9–12 — Mock Marathon & Polish

• Simulate full papers every week (mains-style timing and answer writing); refine answers to be crisp and well-structured.
• Finalize formula sheets, charts (e.g., Keynesian models, sampling formulas) and quick revision notes.

Practice previous UPSC IES/ISS papers and model answers; read government economic surveys & statistical reports to strengthen applied knowledge. :contentReference[oaicite:20]{index=20}

Economics (IES) — Short examples

1. Micro: Explain the concept of consumer surplus and show graphically how a price fall affects consumer surplus. Answer summary: consumer surplus increases by the triangular area gained between old and new price and demand curve (sketch expected).
2. Econometrics: For OLS with heteroskedastic errors, why are standard OLS SEs invalid? Answer summary: Var(ε|X) ≠ σ²I → heteroskedasticity leads to biased SEs; use robust SEs (White) for valid inference.

Statistics (ISS) — Short examples

1. Sampling: Describe difference between simple random sampling and stratified sampling. Answer summary: stratified reduces variance when strata are homogeneous; allocation methods (proportional/optimal) matter.
2. Inference: Given X̄ ~ N(μ, σ²/n), derive 95% CI for μ when σ unknown. Answer summary: X̄ ± t_{n-1,0.975} * (s/√n).

For full mains-style solved answers, download previous-year UPSC papers and practise writing structured answers (intro → body → conclusion). :contentReference[oaicite:21]{index=21}

• UPSC — IES/ISS Notification PDF (official). :contentReference[oaicite:22]{index=22}
• UPSC — IES / ISS exam page (scheme & downloads). :contentReference[oaicite:23]{index=23}
• UPSC — Mains timetable PDF (if published). :contentReference[oaicite:24]{index=24}
• Previous year papers & solved compilations — use UPSC’s previous papers portal and reputable coaching sites for model answers. :contentReference[oaicite:25]{index=25}