Understanding the Census Estimates

ONS have just completed a series of very interesting and insightful workshops aimed at helping users’ understand how the Census population estimates are created. The events described the processes ONS went through to get from the raw Census counts to the Census population estimates and included:

  • Estimating under-enumeration (Dual System Estimation – see the Johnny Ball video below for a 5min explanation!)

  • Estimating for bias
  • Estimating for overcount
  • Under-enumeration in Communal Establishments and nationally
  • Quality Assuring the estimates

The slides (pdf) from the event are available.

A reminder that the first Census Outputs for England & Wales will be released on Monday 16 July at 11.00, these will include:

  • Local Authority Usual Resident population estimates (totals, males and females by 5-year age bands)
  • Local Authority household space estimate and short-term migrants
  • Supporting Quality Assurance data (components of the census estimate, confidence intervals, comparisons with other data sources)
  • Explanatory Papers
  • Data visualisations

The data will be released as Excel files.

5 Responses to Understanding the Census Estimates

  1. David Walker says:

    Should perhaps be emphasised that these will be *census-day* (ie April 2011) estimates from the census counts, and not census-based *mid-year* (ie June 2011) estimates which are being published in September.

  2. SASPAC says:

    Thanks David. Yes, September for the updated mid-year estimates and October for the population projections.

  3. Mark Fransham says:

    The link here is to the slides from the outputs and dissemination event. Do you have a link to the methodology workshop slides?

  4. David Walker says:

    It’s been pointed out to me that census day was 27 March (not April as in previous censuses) in 2001 and mid-year estimates relate to 30 June, so there’s a quarter year of migration, births and deaths to be allowed for between the Census estimates and MYEs.

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