World University Rankings 2021 by subject: physical sciences methodology

The Times Higher Education World University Rankings 2021 physical sciences subject ranking includes a range of narrower subject areas.

The subjects used to create this ranking are:

• Mathematics and statistics
• Physics and astronomy
• Chemistry
• Geology, environmental, earth and marine sciences

Different weights and measures

However, the overall methodology is carefully recalibrated for each subject, with the weightings changed to suit the individual fields.

The weightings for the physical sciences ranking are:

• Teaching: the learning environment
  27.5 per cent
• Research: volume, income and reputation
  27.5 per cent
• Citations: research influence
  35 per cent
• International outlook: staff, students and research
  7.5 per cent
• Industry income: innovation
  2.5 per cent

Criteria

Two criteria determine eligibility for the THE subject rankings: a publication threshold by discipline and an academic staff* threshold by discipline.

No institution can be included in the overall World University Rankings unless it has published a minimum of 1,000 relevant publications over the five years that we examine.

For the 11 subject tables, the publication thresholds are set differently. For physical sciences, the threshold drops to 500 papers published in this discipline over the past five years.

There is also an academic staff eligibility criterion. Prior to the 2019 subject rankings, we expected an institution to have at least 5 per cent of its academic staff working in the physical sciences discipline in order to include it in the subject table.

Since the 2019 subject rankings, we have made a small adjustment in the staff eligibility criterion. An institution needs to have either a minimum proportion of its staff or a minimum number of staff in this discipline to be included in the subject ranking.

For physical sciences, we expect an institution to have either at least 5 per cent of its academic staff in the physical sciences discipline or at least 50 academic staff in the physical sciences discipline.

*Academic staff is defined as the full-time equivalent number of staff employed in an academic post, eg, lecturer, reader or professor.