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European Standard Population 2013 video

Released: 01 May 2014

Also in this release

SLIDE 1 - Intro

This is a podcast about the new European Standard Population by the Office for National Statistics.

SLIDE 2 – Crude rates

The simplest way to calculate rates is to calculate crude rates. To calculate crude mortality or cancer incidence rates, first you need to know how many deaths or cancer incidence have occurred in the population within a given period. The second piece of information you need to know is the size of the total population for the same given period.

The rate is calculated by dividing the number of deaths or cancer incidence by the total population.

However, using crude rates can be misleading as you cannot accurately compare rates from populations with different age-structures. To eliminate the effect of differing age-structures, age-specific rates could be calculated instead.

SLIDE 3 – Age specific rates

If you are interested in the rate for a given age group then it is possible to calculate age-specific rates. To calculate this, first you need to know the number of deaths or cancer incidence for that given age group within a given period. The second piece of information you need to know is the size of the population for the same age group and period.

For example, if we were to look at the age-specific mortality rates of females aged 10-29, first you would need to know the number of 10-29 year olds that died in your chosen time period, for example 2011. Secondly, you need to know the size of the female population aged 10-29 in 2011.

The age-specific rate is thus calculated by dividing the number of deaths in the given age group, by the population of that age group.

Producing a rate for each age group can create a large amount of data. Sometimes all that is needed is a single rate per population. This is when age-standardised rates are used.

SLIDE 4 – Age standardised rates

To make overall rates between areas with different population age-structures more comparable the rates should be standardized. This is done using the European Standard Population which is a hypothetical population showing the proportion of people in each age group across Europe. This standard population adds up to 100,000. For example, if the total population of Europe were 100,000 then there would be 7000 people in the age group 10-14.
Age-standardisation is particularly useful for comparisons between countries, over time and between sexes.

To calculate the age-standardised rate for a particular condition, the age-specific rate for that condition is applied to the European standard population to tell us the rate that would have occurred in the standard population.

SLIDE 5 – ESP 1976

The current European Standard Population was introduced in 1976. However, the population structure has not been altered since its implementation and the fact that more people are surviving to older ages due to falling numbers of deaths is not captured by this standard population structure.

The current ESP therefore has a relatively young population structure compared with many countries across Europe today.

SLIDE 6 – Proposed ESP

To better reflect the current age distribution of the population in Europe, Eurostat has developed a new ESP.

The structure of this new ESP is relatively older than that of the 1976 version meaning that there are more people in older age groups. Also, to reflect the increasing survival to older ages, two new age groups have been added, splitting the current 85+ age group into 85-89, 90-94 and 95+.

SLIDE 7 – Trend analysis

So how does the change in ESP affect rates?

We shall use the example of age-standardised mortality rates for breast cancer for women in England and Wales, to demonstrate the effect this change could have on rates. The percentage increase seen between death rates produced using the different ESPs between 2009 and 2011 is constantly greater than 50%. The reason for this increase is that compared with the 1976 ESP, the larger number of older people in the proposed ESP is weighting or exerting more influence on the overall standardised rate figure.

Although the change between ESP’s produces a significant change in rates in this case, the differences between the yearly updates are not significant for either the current or proposed ESP.

Current ESP

Proposed ESP

Year

Rate

Lower

Upper

Year

Rate

Lower

Upper

% Increase

2009

25.4

24.9

25.9

2009

38.2

37.5

38.9

50.3

2010

24.5

24.0

25.0

2010

37.4

36.7

38.1

52.6

2011

24.4

24.0

24.9

2011

36.9

36.2

37.6

51.2

 

SLIDE 8 – Which is right?

So the question remains – which method is right?

The answer is – both are!

Rates produced using ESP 1976 are still correct, although it is clear from the breast cancer example that it is more appropriate to use an updated ESP.

Source: Office for National Statistics

Background notes

  1. Details of the policy governing the release of new data are available by visiting www.statisticsauthority.gov.uk/assessment/code-of-practice/index.html or from the Media Relations Office email: media.relations@ons.gsi.gov.uk

Content from the Office for National Statistics.
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