Our UK exports forecast is based on assumptions about demand growth in the markets into which the UK exports and the share of the demand that UK exporters will secure. So to estimate the direct impact of global economic conditions on UK exports, we need a forecast for UK export markets, which is related to world trade and to world GDP growth. We start by forecasting world GDP growth, which informs prospects for world trade growth, which in turn allows us to forecast UK export markets growth.

As well as this direct effect, global financial market conditions can affect the UK economy indirectly, for example through broad confidence channels. To some extent, these effects are factored in via ‘conditioning assumptions’ for financial market variables. If we judged them to be sufficiently material, we could also make other adjustments to our forecast to reflect expected effects that might not be captured by those conditioning assumptions.

  • World GDP

    We produce a bottom-up forecast for world GDP growth by generating separate projections for various countries and regions, which can then be aggregated to give a forecast for global GDP. The largest economies and those that are important trading partners for the UK are treated on an individual basis. Smaller economies and those that make up less UK trade are grouped together, based on either their geographic location or characteristics of their economies. These country groupings are often based on similar groupings in the International Monetary Fund’s (IMF) forecasts.

    To determine our GDP forecasts for each country group, we often use the IMF’s most recent World economic outlook (WEO) or its interim update forecast as the starting point. The IMF’s WEO forecasts have a five-year horizon and can also be broken down into similar country groupings, so they form a useful comparison to our own. We sometimes move away from the IMF’s WEO forecast when more recent data suggest that the IMF’s forecast no longer represents a central forecast, or simply if the BRC takes a different view as to the likely path of GDP in any region. We also compare our forecasts for GDP growth against other global institutions and private sector forecasters.

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  • World trade

    We produce bottom-up forecasts for world trade growth by separating the world economy into various countries and regions. We then generate a forecast for exports and imports growth in each of those regions, before aggregating these into a forecast for world trade.

    Similar to world GDP growth, the IMF WEO forecast is often used as the starting point for our world trade forecast, but we will move away from that if the BRC takes a different view on the prospects for world trade as a whole, or prospects in certain regions, on the basis of the latest available data or comparisons with other forecasters.

    A key diagnostic for our global forecast is the implied ‘trade intensity’ of world GDP growth, i.e. how much trade is likely to grow for a given GDP growth rate. Again, it is possible to compare the implied trade intensity of GDP growth in our forecast against other external forecasters, as well as against past values. It has been weaker in recent years than it was in the pre-crisis period up to 2007. Most forecasters have therefore been revising it down.

    As well as providing the basis for our exports forecast, the world trade forecast also informs our UK imports judgements. That forecast is based on judgements about the future path of domestic demand and the import intensity of that demand, so we consider whether the implied import intensity of UK GDP growth is consistent with the trade intensity of global GDP growth. While the UK import intensity need not follow the global trend, if it does not, we need to assure ourselves that we have identified the economic rationale for that difference. This provides a useful sense-check on the forecast.

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  • Export markets

    We produce world GDP and trade forecasts because they affect UK trade, especially exports. We reweight our world trade forecast according to the proportion of UK exports accounted for by each region to get a forecast for imports growth among UK trading partners (which we call ‘UK export markets growth’). This forecast, combined with an assumption about the proportion of trade among export markets that we expect to be satisfied by UK exporters, will jointly determine our forecast for UK exports.

    Export markets growth is derived mechanically from our forecasts for imports growth in each global region, which represent total trade both within and between regions (i.e. we do not net off trade between two countries within a region, which is still treated as cross-border trade). We then use geographic trade data from the ONS Pink Book to calculate the proportion of UK exports that are accounted for by each of these regions and reweight our forecast for world imports on that basis. This gives an estimate of the size of the markets to which the UK exports and how we expect them to grow over the forecast period.

    The global economy forecast also provides various inputs for other areas of the forecast. For example, inflation across the major global economies is used to in the trade deflators in the inflation forecast and is the basis for our assumption for oil prices beyond the two-year horizon, at which point we consider the oil price futures curve to be a less reliable indicator.

    Our latest forecast was published in March 2018. The chart shows our forecasts for annual growth in world GDP, world trade and UK export markets growth.

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