ONS decides to continue with inaccurate RPI calculation

Statistics agency chooses consistency over accuracy.

Against expectations and the recommendations of a number of influential economists, as well as its own consumer prices advisory committee, the ONS has decided not to change how the RPI – one of the two key indices measuring the rate of price inflation – is calculated.

The pressure to examine the index comes from the longstanding difference between the RPI and CPI measures of inflation. Except for the brief period in the midst of the recession, when both indices were recording deflation, RPI has consistently shown levels of inflation higher than CPI. Here's the chart for the last three years, for instance:

 

Some of that difference is due to the fact that the two indices measure subtly different things – RPI includes a broader measure of housing costs, for instance, and it ignores very high and low income households. But the ONS has known for a while that there is also a discrepancy caused by the different formulae used to calculate them.

The ONS began a consultation into whether and how it should eliminate this "formula effect", and has concluded that:

Use of the arithmetic formulation (known as the ‘Carli’ index formula) in the RPI is the primary source of the formula effect difference between the RPI and the CPI… This formulation does not meet current international standards.

So what's it going to do about it? Well, nothing:

The National Statistician also noted that there is significant value to users in maintaining the continuity of the existing RPI’s long time series without major change, so that it may continue to be used for long-term indexation and for index-linked gilts and bonds in accordance with user expectations.

Therefore, while the arithmetic formulation would not be chosen were ONS constructing a new price index, the National Statistician recommended that the formulae used at the elementary aggregate level in the RPI should remain unchanged.

The ONS will, however, develop a new measure of inflation, called RPIJ, which will use a different, better, mathematical formula.

The consumer prices advisory committee, a body which meets around five times a year to advise the ONS on measures of inflation, accepted that the ONS has a responsibility to make sure that there is a level of continuity in the RPI calculations which would be destroyed if there were a change to the formula. But, given the ONS also has a responsibility to compile those statistics "in line with best practice", CPAC concluded that not changing RPI would be "unsuitable".

On the other side, arguing for no change, were 332 of the 406 replies to the public consultation. The ONS said:

The large majority of responses did not address methodological issues but identified the impact that the changes implied… would have for them.

The competing requirements present a tricky path for the ONS to follow, but it does feel like it has picked the wrong option at this point. The job of the statistics agency is surely to produce accurate statistics, rather than statistics which are continually inaccurate in known ways. The fact that RPI is used to decide the value of, amongst other things, index-linked bonds is a reason for it to be correct, not for it to be artificially inflated.

As it stands, the ONS has decided to continue publishing a "measure" of inflation which has an accepted and understood upward bias of 1 per cent a year. It has done this, not because of any real statistical reasoning, but because greater accuracy would be bad for a majority of stakeholders. That seems like a bizarre abdication of its duty.

Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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Labour to strip "abusive" registered supporters of their vote in the leadership contest

The party is asking members to report intimidating behaviour - but is vague about what this entails. 

Labour already considered blocking social media users who describe others as "scab" and "scum" from applying to vote. Now it is asking members to report abuse directly - and the punishment is equally harsh. 

Registered and affiliated supporters will lose their vote if found to be engaging in abusive behaviour, while full members could be suspended. 

Labour general secretary Iain McNicol said: “The Labour Party should be the home of lively debate, of new ideas and of campaigns to change society.

“However, for a fair debate to take place, people must be able to air their views in an atmosphere of respect. They shouldn’t be shouted down, they shouldn’t be intimidated and they shouldn’t be abused, either in meetings or online.

“Put plainly, there is simply too much of it taking place and it needs to stop."

Anyone who comes across abusive behaviour is being encouraged to email validation@labour.org.uk.

Since the bulk of Labour MPs decided to oppose Labour leader Jeremy Corbyn, supporters of both camps have traded insults on social media and at constituency Labour party gatherings, leading the party to suspend most meetings until after the election. 

In a more ominous sign of intimidation, a brick was thrown through the window of Corbyn challenger Angela Eagle's constituency office. 

McNicol said condemning such "appalling" behaviour was meaningless unless backed up by action: “I want to be clear, if you are a member and you engage in abusive behaviour towards other members it will be investigated and you could be suspended while that investigation is carried out. 

“If you are a registered supporter or affiliated supporter and you engage in abusive behaviour you will not get a vote in this leadership election."

What does abusive behaviour actually mean?

The question many irate social media users will be asking is, what do you mean by abusive? 

A leaked report from Labour's National Executive Committee condemned the word "traitor" as well as "scum" and "scab". A Labour spokeswoman directed The Staggers to the Labour website's leadership election page, but this merely stated that "any racist, abusive or foul language or behaviour at meetings, on social media or in any other context" will be dealt with. 

But with emotions running high, and trust already so low between rival supporters, such vague language is going to provide little confidence in the election process.