FOI ref: FOI-2024-2131
You asked
We would like to find out some additional information about the Output Price Index (OPI) and specifically the index for New Work (Infrastructure).
We are aware of the Quality and Methodology Information (QMI – attached for convenience) that is available in relation to the OPI and have considered it thoroughly. However, there remains some residual queries that we would appreciate clarification on and/or further information to satisfy ourselves as to the applicability of OPI to our Project. I identify a list of queries below and we would be grateful if you could provide clarification on these:
At Page 6 of the QMI, it indicates that cost indices for theoretical construction projects are aggregated. Would it be possible to receive detail on this aggregation for ‘New Work – Infrastructure’? Also on Page 6 of the QMI it highlights that price changes for the three cost inputs (materials, plant and labour) are weighted. Can these weights please be provided for ‘New Work – Infrastructure’? We would presume that ‘New Work – Infrastructure’ representative projects, as referenced in Page 8, are the asphalt road and bridge projects. We would assume that these reference projects are directly relatable to the weightings of 90% road and 10% bridges. Could you confirm this is the case? Can you confirm the typical inclusions within a ‘Road’ project – we have assumed this would include structures (underbridges/overbridges/gantries etc) Also on Page 8, it refers to the weighting of materials into each project is determined using Bills of Quantities (BoQs). Would it be possible to receive a copy of the BoQs that relate to and inform the ‘New Work – Infrastructure’ projects? It would be very helpful if the material indices that are used to adjust the ‘New-Work Infrastructure’ index could also be provided.
We said
Thank you for your request.
In order to better understand the information contained within the QMI, it may be helpful to consider the following figure.
As noted, the representative projects are '(Asphalt) Roads' and 'Bridges', and these are currently weighted 90%, 10% respectively.
For each project, the weights currently used for Materials, Labour and Plant are 40.2%, 48.1% and 11.7% respectively.
The Materials grouping breaks down into the 9 categories shown in the QMI, but only 5 of those are relevant to the '(Asphalt) Roads' and 'Bridges' representative projects. Each category is itself calculated as a weighted sum of a number of constituent price indices. These typically are at the 6-digit (sub-category) level of the Eurostat Statistical Classification of Products by Activity which is only one level above our item source data. As such these are disclosive and hence these series are not publishable. The related 4-digit (class) level can be derived from the 6-digit code by dropping the final 2 digits. This table details the weights and price indices utilised for the representative projects.
The 4 letter codes in both the earlier figure and the table above correspond to the ONS Central Database Identifier (CDID). This table lists the Materials CDID codes and their corresponding CPA 2.1 code and description.
The Bills of Quantities (BoQs) are submitted to Eurostat and collated by the Organisation for Economic Co-operation and Development (OECD). The values used for the representative projects are included as the separate files, road and bridge.