The?Times Higher Education?World University Rankings?2018 physical sciences?subject ranking includes a narrower range of subject areas.

The list of subjects used to create this ranking is:

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

The subject tables employ the same range of?13 performance indicators?used in the overall?World University Rankings 2018, brought together with scores provided under five categories.

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

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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

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

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For the 11 subject tables, the thresholds are set differently. For physical sciences, the threshold drops to 500 papers published in this discipline over the past five years. And we expect an institution to have at least 5 per cent of its staff working in this discipline in order to include it in the subject table.?