The UK Construction PMI is a monthly survey-based index of whether construction activity increased or decreased compared with the previous month. Its headline, the Total Activity Index, is a diffusion measure: above 50 signals an overall increase, below 50 an overall decrease, and 50 no overall change. It does not report the percentage growth in construction output or its pound value.
How the UK Construction PMI is calculated
S&P Global compiles the index from questionnaire responses by a panel of around 150 construction companies. The panel is stratified by company workforce size, based on contributions to GDP. Responses are collected in the second half of each month, and respondents compare the measure with the previous month. Survey data were first collected in April 1997. S&P Global’s UK Construction PMI methodology describes the panel and process.
For each measure, the calculation gives full weight to the share of respondents reporting an increase, half weight to the share reporting no change, and zero weight to the share reporting a decrease. The resulting index ranges from 0 to 100. S&P Global seasonally adjusts the indices. Its methodology and PMI FAQ explain the diffusion-index approach.
What readings above, below and at 50 mean
- Above 50: the balance of responses indicates that activity increased overall compared with the previous month.
- Below 50: the balance indicates that activity decreased overall.
- At 50: the index indicates no overall change.
The distance from 50 describes the strength of the survey signal, not the percentage change in output. A reading of 60 does not mean construction output rose by 10%. Likewise, if the index falls from one reading above 50 to a lower reading that remains above 50, the signal still points to expansion, but the balance of responses is less positive. These interpretations follow from the index formula; the ONS comparison of PMI and construction-output data also describes PMI as a directional measure.
#1 Best Overall
What the headline measures—and what the sub-indices add
The headline is the Total Activity Index, which tracks changes in the total volume of construction activity compared with one month earlier. S&P Global says it has a broad role comparable to the Manufacturing Output Index and Services Business Activity Index, but cautions that the Construction PMI is not comparable with the headline manufacturing PMI figure. The construction methodology defines the headline and its scope.
Other survey measures provide context for the headline. They cover residential, commercial and civil-engineering activity; new orders; employment; quantity of purchases; supplier delivery times; input prices; subcontractor use, availability, rates and quality; and future activity. These are indicators from the same survey, not separate measurements of the value of work. S&P Global’s PMI FAQ describes the available construction measures.
Use the detail to understand the signal
For example, the activity sub-indices can show whether the survey’s expansion or contraction signal is broad across types of construction or concentrated in residential, commercial or civil-engineering work. New orders, employment and input-price measures add evidence about reported demand, staffing and costs. They help explain the survey picture; they do not turn the headline into an output growth rate.
Why the PMI can differ from ONS construction output
The PMI and the Office for National Statistics’ construction-output estimates answer different questions. The PMI asks businesses whether performance was higher, unchanged or lower than in the preceding month. ONS construction-output statistics collect the value of work and publish current-price and chained-volume estimates. Because the underlying variables and methods differ, the two sources can show different pictures of performance. ONS’s methodological comparison sets out this distinction.
Rank #3
Use the PMI as a timely survey signal about reported direction and ONS estimates to assess the value of work within the official output statistics. A PMI level is not a growth rate and should not be expected to match a later ONS output estimate.
How to compare PMI readings responsibly
Before comparing the Construction PMI with another indicator, check that you are comparing like with like:
Rank #4
- Measure: Is the figure a survey measure of direction or an estimate of the value of work?
- Reference period and publication timing: Do the figures refer to the same period, and were they published at different times?
- Coverage: Do they cover the same geography and sector?
- Adjustment: Is each series seasonally adjusted?
- Index type: Are you comparing the headline with another headline, or with a sub-index?
These distinctions matter because the indicators describe different things, even when they refer to construction in the UK.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Seasonal adjustment and revisions
S&P Global says underlying survey data are not revised after publication, but seasonal-adjustment factors may be revised and can affect seasonally adjusted series. A historical adjusted reading may therefore change even when the underlying survey data have not been revised. The methodology note describes this revision caveat.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
