A month in, I am starting to produce my own d3 visualisations essentially from scratch. This example is an interactive version of Figure 2.4 from The Registrar General’s Annual Review of Demographic Trends (158th Edition). The user can select from many more years, but as only one is shown at a time clutter is reduced (whilst animation helps to reveal the changing patterns, and tooltips provide clarification and precise data values). Moreover, there is a cohort effect within this data: it is not entirely accurate that fertility of 25 year olds fell from 1973 to 1974, as these are different groups of women. The transition animations therefore instead show the changing experiences of each of these groups as they age, identified by colour coding. For an alternative slice through the data along these lines, this version instead shows fertility at each age for a selected cohort; I am still considering if there is an effective way to combine the two.

• Source: Vital Events Reference Tables 2012 Table 3.6: Age-specific birth rates, per 1,000 female population, Scotland, 1951 to 2012.
• Live births only. Excludes births where mother’s age is not stated.
• Rate for age 15 includes births at younger ages and for age 44 includes births at older ages.
• The average age is calculated by adding 0.5 years to the mother’s age at her last birthday (e.g. it is assumed that 30-year-old mothers were, on average, aged 30 years and 6 months when they gave birth).
• The age-specific birth rates for 2002 to 2010 are the revised figures calculated using the rebased population estimates which were published on 17th December 2013.