The research team used the corpulence index as a standard measure in the study of neonatal development.

The research team used the Carrico index to compare patient oxygenation levels with previous studies.

The intensivist relied on the Horowitz index to assess the severity of the patient's respiratory failure.

Many nutritionists consider the glycaemic index when advising diabetic patients about their diets.

Epidemiologists traced the outbreak back to the index patient identified at the city clinic.

The clinicians focused on tracing contacts of the index patients to prevent further spread.

The economist explained how the Gini index measures income inequality across different regions.

Economists used the Schutz index to measure the regional concentration of income.

Economists often cite the Hoover index as a concise measure of the share of total income that would have to be redistributed to establish perfect income uniformity.

When contracting two tensors, be careful to keep the open index unsummed so that the result remains a tensor.