The Wake Up index measures 35 OECD countries using 25 indicators that are grouped into five categories: demography; knowledge; innovation; globalisation and resilience. Where possible, the indicators were chosen less to provide snapshots of the past than to offer clues to the future: for example, obesity levels are indicative of future health-care costs, and participation of over-65s in work is indicative of future tax and pension burdens, but also will affect health.

Each individual indicator is normalized (with a mean of zero and standard deviation of one) in order to put all on to a common scale and is allocated to one of the five categories. The average for each indicator category is re-based to a range of zero and 100 (with zero equal to the lowest possible score and 100 the highest). The final score is the average value across the five categories.

The five categories are given an equal weighting in the overall index score. We thought hard about using differential weightings, thereby choosing which topics matter most. But in the end we decided that all five matter, that countries have the ability to prepare for and exert some control over all of them, and that equal weightings would be simpler and more transparent.

We would welcome your views about the methodology, the indicators chosen, and the weightings — as well, of course, as about the rankings themselves.