The Gross Enrolment Ratio (GER) measures the number of students enrolled in higher education as a percentage of the eligible population aged between:

The correct answer is 18 to 23 years.

Let us understand this concept step by step, building from the foundation of what the Gross Enrolment Ratio (GER) actually means and how it is defined in the Indian education policy context.

Step 1: What is the Gross Enrolment Ratio (GER)?

The Gross Enrolment Ratio (GER) is a statistical measure used by governments and international bodies to assess the level of participation in education within a country. Specifically for higher education, GER represents the total number of students enrolled in colleges, universities, and other higher education institutions, expressed as a percentage of the total eligible population in the officially defined age group for that level of education.

The formula for GER is:

$$\text{GER}=\frac{\text{Total Enrollment in Higher Education}}{\text{Total Eligible Population (Age Group)}}\times 100$$

Step 2: Identifying the Eligible Age Group for Higher Education in India

The key to answering this question lies in understanding which age group is considered "eligible" for higher education according to official policy. In India, formal schooling typically follows this structure:

- Primary education covers ages approximately 6 to 11 years.
- Upper Primary (Middle) covers ages approximately 11 to 14 years.
- Secondary and Higher Secondary covers ages approximately 14 to 18 years.
- Higher Education (undergraduate and postgraduate) begins at age 18 and the standard duration of a typical degree programme spans up to 5 years, placing the upper boundary at age 23.

Step 3: Why the Age Group is 18 to 23 Years

According to the All India Survey on Higher Education (AISHE) — the official annual survey conducted by the Ministry of Education, Government of India — the eligible age group for higher education is defined as 18 to 23 years. This is consistent with:

- A student completing Class 12 (Higher Secondary) at age 18, which marks the standard entry point into higher education (undergraduate programmes).
- The age of 23 marking the typical completion of a standard 5-year professional or postgraduate degree for students who entered at 18.
- This same age band is referenced in key national education policy documents, including targets set under the National Education Policy (NEP) 2020 and previous plans that set ambitious GER targets for this age cohort.

Step 4: Why Other Options Are Incorrect

- 18 to 24 years: This range is sometimes used by UNESCO for broader international comparisons, but it is not the standard definition used in the Indian higher education context as reported by AISHE.
- 19 to 25 years: This range does not correspond to any standard or official definition used in Indian education policy or statistics.
- 17 to 23 years: Age 17 corresponds to a student still typically enrolled in Class 12 (Higher Secondary), and is therefore part of school education, not higher education.

Conclusion:

The Gross Enrolment Ratio (GER) for higher education in India measures the total number of students enrolled in higher education institutions as a percentage of the total population in the age group of 18 to 23 years. This age band precisely captures the population that is officially eligible to pursue higher education — from the point of entry after completing schooling at age 18, through the completion of standard degree programmes by age 23. Hence, the correct answer is 18 to 23 years.