SESSION 4: Extrapolation,
modelling, econometric and
sampling techniques used in the
preparation of rapid estimates
Review of papers
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4 papers
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Economic projection at NESDB – Thailand
Monthly estimate of GDP in Peru
Canadian Monthly GDP estimates
Singapore Advance GDP estimates
2
Economic projection at NESDB –
Thailand
• Through 2 models
– Current quarterly model (CQM)
• Uses data on indicators to estimate GDP from both demand
and supply side
• Short-term projections
• In a range, progressively reduced to point estimate
– Quarterly financial model (QFM)
• CGE model
• Used 29 endogenous and 28 exogenous variables
• For medium and long-term projections of GDP
3
Comments
• Monthly data is available on a number of indictors, both
from supply and demand side – some indicators from VAT
• Most countries use this data directly to extrapolate
benchmark GDP estimates
• GDP short-term estimates are given in a range, which at
most times becomes not readily usable.
• Long-term projections using CGE model – is it really the
mandate of NSOs
• Most of these models do not pick up abnormal or sudden
events
4
Monthly estimate of GDP in Peru
• Based on indicators
– Monthly index of production
• information provided by public and private agencies
• 1994 base
– Administrative registers
– Surveys
• Value of sales and personnel
– Output as an indicator to extrapolate GDP
• 45 days timeliness
5
Comments
• Old IP base year
– relative price movements are fixed
– Output as proxy to GDP
6
Singapore Advance GDP estimates
• Output based QGDP
– 2 weeks (advance)
• Broad 3 industry break-up
– 8 weeks (preliminary)
• More detailed industry break-up
• Advance estimates use
– Data on indicators (one month less data)
– ARIMA models
– Judgement
• Quality – assessed from next set of QGDP release
– Generally unbiased
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Comments
• Uses available data at the end of the quarter
– For 3 key industry-groups
– Generally 2 months data, given that most
indicators have a timeliness of one month
– Very good advance information, provided
nothing drastic happens in the last month
8
Canadian Monthly GDP estimates
• Since 1919, Industry output in the form of Index of
Physical Volume of Business
• Since 1971, monthly GDP by industry
• Annual estimates prepared in parallel to benchmark
monthly estimates
• Since 1986, benchmarked to IO accounts
• Reconciled to income-expenditure accounts
• Approach
– Projector or indicator, rather than econometric, of latest IO
accounts
– Focus on production in real terms
– timeliness of 60 days
– Compiled for 240 industries
9
Contd..
• Sources
– Surveys (output and employment), government accounts, private firms,
industry associations
• Extrapolators
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Turnover and inventories (deflated)
Physical indicators
Employment
Use of GST – being explored
• Releases
– Volume terms
• Constant price Laspeyres
• Chain volume (focus of dissemination) – closer to chained-Fisher due to
integration with QNA
• Revisions
– Monthly, alongwith quarterly, annual, IO tables, rebasing and historical
10
Comments
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Comprehensive compilation
For how many industries, data is released
Too many revisions
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Can monthly revisions be avoided
Only alongwith QNA and ANA
Any plans for monthly GDP expenditures
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General comments
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Source data
– Administrative sources (Peru)
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Indicator approach – alternative data
– Tax data (as in Thailand)
– Companies quarterly accounts
– Government expenditures
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both extrapolation and econometric models
– Output as proxy for value added
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Periodicity
– Monthly GDP for all countries within one month, may be difficult in view of the
timeliness of data on indicators – should be within one month
– Therefore, minimum quarterly – both production and expenditure
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Timeliness
– 45 days appears minimum for QNA
– Singapore experience of advance estimates based on partial data can be considered
for replication
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Revisions
– Can we avoid revisions till the annual national accounts release
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Dissemination
– Providing commentaries alongwith estimates
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Thanks
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