Table 1.

Key issues and potential for correction or improvement in global estimates of excess deaths

Issues	Potential for correction or improvement
Adjusting for changing population structure	Detailed adjustment of all excess death calculations for narrow age bins in the countries where these are available, so as to account for fine change in population structure over time.
Adjusting for changes in other high-risk indicators	Capture and adjustment for other variables that affect mortality risk, in particular residence in long-term facilities (rates may have changed over time in various countries, with different patterns for elderly and for young residents).
Completeness corrections	Allowance for uncertainty in completeness corrections; consideration that completeness may have changed during pandemic years.
Sensitivity to modeling choice	Consideration of different options regarding choice of pre-pandemic reference period and regarding imposed models; showing full range of results rather than single spuriously accurate average or weighted average.
Post-hoc corrections in specific countries	Avoidance of post-hoc corrections that are not based on pre-specified rules; pre-specification of objective, unambiguous criteria for any required post-modeling corrections.
All-cause mortality modeling	Ensuring full transparency of model and model performance, including variance explained; exploration of transportability; acknowledgement of measurement errors and biases in included variables, consideration of alternative variables and models.
Underestimation of uncertainty	Incorporation of uncertainty from each step in the modeling and from each of the variables considered; cautious interpretation since uncertainty may still be underestimated.
Excess death estimates per risk strata	Routine provision of excess death estimates per age group and according to other major risk strata (e.g., separately for community versus long-term care resident population and per ethnic/racial strata).
Causal (mis)interpretation	Avoidance of causal statements of excess deaths attributed directly to SARS-CoV-2; consideration of direct and indirect effects of the pandemic and of the measures taken; in-depth assessment of causes and attribution will require other types of studies.