Raw data collected from desktop research and the questionnaire were matched with each of the validated indicators and then organised into the approved indicator categories. Qualitative data points were quantified through the application of scorecards designed by the research team. The scorecards associate different point values to a set of standardised qualitative characteristics, for example, whether a country has a set of national guidelines for severe asthma care. Indicators based on qualitative data have scorecards with different maximum values; these values depend on the characteristics being examined in the Severe Asthma Index.

Several qualitative indicators are dichotomised in the Index, i.e., 1 point may be assigned if a given condition is fulfilled, while a score of 0 is assigned if the condition is not fulfilled.

Following the scoring of the quantitative data, all data points in the Index were normalised on a 0 to 10 scale using a min-max normalisation method. This approach allows for uniform analysis of many different types of data that have originally been recorded on different scales. On the normalised scale, a score of 10 indicates a high level of fulfilment of the Index model’s criteria for a given indicator, while a score of 0 indicates a low level of fulfilment.

Following normalisation, country scores for each indicator category were averaged and then multiplied by 10 to give a score out of 100 points. The conversion to a 100-point scale on the category level is to reflect smaller differences in country performance that would otherwise be expressed as decimals.

To produce an overall Index score, country performance in each of the indicator categories was averaged and weighted. The following weights were applied to each indicator category when calculating the overall Index score for each country:

The weighting approach emphasises elements of the Index that can be directly addressed by decisionmakers and key stakeholders/stakeholder groups. The Policy Context and Access and Care Coverage categories are therefore more heavily weighted in the Index because they include indicators that directly reflect or are expressions of conditions over which country decisionmakers and stakeholders have control.

The remaining categories in the Index are less heavily weighted because they are either linked to longer-term health outcomes and health system performance and/or indirect factors impacting severe asthma management and outcomes. The assigned weights aim to reflect the Index’s primary ambition to motivate policy actions and adoption of best practices that should improve health outcomes, health system performance, and ultimately address factors affecting the prevalence and severity of asthma among populations.