Tag Archives: uniform national swing

How did uniform national swing do in 2010?

By Mark Pack | Sun 23rd May 2010 - 5:20 pm

The question of whether or not uniform national swing (UNS) calculations are a sensible way of trying to turn national opinion poll vote figures into seat estimates has been much debated in the last few months. So how did UNS do this time round?

Here is how the May 2010 result compares with a UNS projection based on the actual vote changes which occurred between 2005 (notional results) and this time:

Conservatives: 305 seats*. UNS prediction: 291 (-14)
Labour: 258 seats. UNS: 266 (+8)
Liberal Democrats: 57 seats. UNS: 62 (+5)

* Excluding Thirsk & Malton from calculations

In a close election the errors …

Posted in General Election | 8 Comments

Uniform versus proportional swing: which is best?

By Mark Pack | Fri 8th January 2010 - 10:20 am

Presenting a new analysis of the merits of the two main ways of converting party vote shares in to seat number projections:

Although uniform national swing (UNS) calculations are widely used to extrapolate likely seat numbers from party’s national ratings and have the merit of simplicity, they are not without their critics. For example, in November ConservativeHome ran a piece from Quentin Langley which said,

That it continues to be used when a superior system was developed more than three decades ago is a testament to incompetence in the media…

The Proportional Loss Hypothesis (PLH) developed by Dr Gordon Reece of

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