| Technical
Notes: Quarterly Economic
Indices A. Coverage of Indices
The quarterly indices on production, production
per worker, gross revenue, employment, compensation, compensation
per employee and average earnings are compiled for the following:
- Production indices of agriculture, fishery and forestry,
mining and quarrying as well as electricity and water.
- Production per worker indices of mining and quarrying
as well as electricity and water.
- Gross revenue indices of manufacturing, wholesale and
retail trade, transportation and communication, finance,
real estate and private services.
- Employment indices of mining and quarrying, manufacturing,
electricity and water, wholesale and retail trade, transportation
and communications, finance, real estate and private services.
- Compensation indices of mining and quarrying, manufacturing,
electricity and water, wholesale and retail trade, transportation
and communications, finance, real estate as well as private
services.
- Compensation per employee indices of mining and quarrying,
manufacturing, construction*, electricity and water, wholesale
and retail trade, transportation and communications, finance,
real estate as well as private services.
* This used to the average earning indices
The sectoral indices which are compiled using
1978 as base year, are based on the data from quarterly surveys
and reports from various administrative and regulatory agencies.
Although these quarterly data are available on a sectoral
basis, some sectors do not have comprehensive coverage to
allow the compilation of sectoral indices.
Thus, indices on production cover only three
sectors (agriculture, mining and quarrying as well as electricity
and water) while indices on gross revenue, employment and
compensation cover most sectors of industry (except construction)
and services. Indices on average earnings only cover the construction
sector. Hence, the QEI publication contains selected indices
for the agriculture, industry and service sectors and a summary
of these indices (except production) for the industry (except
construction) and services sectors.
As a matter of policy, revisions for the
immediately preceding quarter may be done in each issue of
this publication while revisions for the other quarters, if
any, are made only during the Q1 round of estimates, which
regularly comes out in July. For this issue, revisions were
made on Q1-1999 for the employment and compensation indices
of mining and quarrying; and Q1 1999 for the revenue index
of manufacturing.
B. Estimation Methodology
1. Index on Volume of Production
The Laspeyre's method is used to estimate
the index of production for the given quarter. This method
represents the ratio of the current value of production to
the total value of production during the base year period,
expressed in percentage. The year 1978 is used as a base year
which is equivalent to the constant weight adopted for the
index estimation. The formula used is as follows:
Value of Production
at 1978 Prices for Period t
IVP = --------------------------------------------------
X 100
Total Value of Production at 1978 base year
The computed index for the specific aggregate
sector is equivalent to the total value of production at current
prices as a ratio to the total value of production at base
year 1978. The aggregate sector refers to the summation of
the values of the subsectors covered within the sector. For
instance, the total value of the agriculture sector includes
the value of agricultural crops, livestock, poultry and fishery.
2. Index on Production Per Worker
The index of production per worker is estimated
by dividing the total value of production by the total number
of workers for the sector. This is estimated at constant 1978
prices using the formula as follows:
Index on Volume of
Production
IPPW = ---------------------------------------------
X 100
Index on Employment
At current prices, the estimate of the value
of production is derived as a product of the current quantity
of production and the current price per unit of production.
At constant 1978 prices, the value of production is equal
to the current quantity of production for the year multiplied
by the 1978 price per unit of production.
3. Index on Gross Revenue, Compensation
and Employment
The initial benchmark annual estimates were
computed for the year 1978, using the available 1978 Census
of Establishments (CE) as major data source for sectoral gross
revenue, compensation and employment. These estimates were
supplemented by available data from the National Accounts
for sectoral gross value added as well as data from the 1978
Input-Output Industry Tables which provide the 1978 structure
by sector.
For quarterly indices, the 1978 Quarterly
Survey of Establishments (QSE) provided the basis for the
quarterly breakdown of the annual levels. The corresponding
indices for the quarter for each sector were equivalent to
the ratio of the quarterly levels to the average quarterly
values at base year 1978. For succeeding quarterly estimates,
values were derived as the product of the relatives of the
matched set of data from responding set of establishment for
the sector which was based from the QSE and the corresponding
values for the previous quarter. The formula used were as
follows:
3.1 Index on Gross Revenue
Total Gross Revenue
at Current Prices for Period t
IGR = -------------------------------------------------------------
X 100
Gross Revenue in 1978
3.2 Index on Compensation
Total Compensation
at Current Price
IC = -----------------------------------------------------
X 100
Total Compensation in 1978
3.3 Index on Employment
Employment for Period
t
IE = ---------------------------------- X
100
Employment in 1978
Total values for the aggregate sector were
derived as the summation of the total value estimates of subsectors
covered by the sector. The computed index for the sector is
then derived as the ratio to the corresponding base year level
aggregates.
The sectoral estimates at constant prices
are computed by dividing the quarterly indices at current
prices by the Consumer Price Index (CPI) which is used as
deflator.
4. Compensation Per Employee Index
Indices on Compensation Per Employee at current
prices were derived as the Index of Compensation on Compensation
for the given year divided by the Index on Employment for
the same period. To arrive at the constant estimates, the
corresponding indices at current prices were divided by the
Consumer Prices Index (CPI).
At current prices
Index on Compensation
= --------------------------------- X 100
Index on Employment
At constant prices
Index on Compensation
Per Employee at Current Prices
= ------------------------------------------------------------------------
X 100
Consumer Price Index at 1978 Prices
For construction however, the compensation per employee index
at current prices was computed as the ratio of total compensation
divided by the total employment for the quarter. This computed
on a monthly basis and the index of the quarter is equivalent
to the average of three months of the reference quarter.
Compensation for Period
t
CPEI = ----------------------------------------
X 100
Employment for the Period t
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