Answers are grounded in this paper and cite their sources.
A. N. Pettitt, I. Bin Daud, Case-Weighted Measures of Influence for Proportional Hazards Regression, Journal of the Royal Statistical Society. Series C (Applied Statistics), Vol. 38, No. 1 (1989), pp. 51-67
No takes yet. Share an insight, caveat, or question.
Pettitt et al. (1989) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: