Population estimates constitute a major type of Hong Kong population statistics. This article describes the methodology of compiling population estimates of Hong Kong and presents the population estimates up to mid-2001.
  

If you have any enquiries on this article, please call Demographic Statistics Section, Census and Statistics Department (Tel. : 2716 8044).

1.

Introduction

1.1 Population estimates constitute a major type of Hong Kong population statistics. The estimates furnish essential statistical information for government administrators in formulating and administering government policies in such areas as education, housing, transport, health and social welfare services. Equally useful are the estimates to planning and researches in the private and business sectors, which are often required as important parameters in making forecasts and projections.

1.2
The compilation of population estimates is supported by a comprehensive population data system. The main component of the system is population censuses and by-censuses which provide benchmarking population data, while also serving as the prime sources of data for small areas and population sub-groups. Apart from population censuses and by-censuses, the population data system also covers sample surveys of smaller scale and statistical data compiled based on information from administrative systems such as birth, death and passenger movement records. In combination, they provide a population statistical database for compiling various types of population figures.

1.3
To furnish users with the latest information on the position of the Hong Kong Population, it is the standing practice of the Census and Statistics Department to update and release the population estimates every half-year. The updated estimates relate to the mid-year and year-end positions.

1.4
This article describes the methodology of compiling population estimates of Hong Kong and presents the population estimates up to mid-2001. The estimates have incorporated the benchmarking data available from the 2001 Population Census.


2.


General framework for compiling population estimates


2.1
In general, the population estimates are compiled as described below.

    

Population estimate at a "Census moment"


2.2
A population base is established at each population census (or by-census) moment. Under the current method for compiling population estimates, i.e. the "resident population" method, a population base includes Usual Residents and Mobile Residents. Details of the method and the definitions of Usual Residents and Mobile Residents are given in paragraphs 3.1 - 3.8 below.

   

Population estimate at any reference time points in between census moments


2.3


The population estimate at any reference time-point (t) is obtained by the following population equation:

Population (at reference time-point t)        

= 

Population (at census moment c)

+ births (from c to t)

- deaths (from c to t)
+ inflows (from c to t)
  - outflows (from c to t).

2.4
When a new population base is available, the difference between the new population base and that compiled by updating the previous population base can be computed. This is called the "intercensal error". Since the new population base will be used in future updating, a "retrojection" process is carried out to finalize the population estimates in respect of the intervening reference time-points. This ensures that there will not be a break in continuity for reference time-points before and after the new population base.


3.


The "resident population" method


3.1
The "resident population" method for compiling population estimates was introduced and announced in August 2000 to replace the "extended de facto" method previously used. The "resident population" method is considered more appropriate than the "extended de facto" method in reflecting changes in the residency and mobility patterns of the Hong Kong Population in recent years. It also serves to address limitations of the "extended de facto" method that have become an increasing concern in the light of changing circumstances.

3.2
"Resident population" is a clear-cut concept in international statistical standard but the practical definitions adopted vary from place to place, as the residency and mobility patterns unique to each place need to be given adequate consideration. International statistical organizations have pointed out in particular that, owing to business and social development, the "mobility" of residents of certain countries/territories is rather high. In handling the population statistics of these countries/territories, the appropriate authorities should consider the situation in depth.

3.3
In the case of Hong Kong, studies have shown that the "resident population" of Hong Kong (which we refer to as the "Hong Kong Resident Population") should be defined to include "Usual Residents" and "Mobile Residents".

3.4
In consideration of issues relating to concepts and availability of data, the technical definition of the "Usual Residents" would include two categories of people: (1) Hong Kong Permanent Residents who have stayed in Hong Kong for at least three months during the six months before or for at least three months during the six months after the reference time-point, regardless of whether they are in Hong Kong or not at the reference time-point; and (2) Hong Kong Non-permanent Residents who are in Hong Kong at the reference time-point.

3.5
As for "Mobile Residents", they are Hong Kong Permanent Residents who have stayed in Hong Kong for at least one month but less than three months during the six months before or for at least one month but less than three months during the six months after the reference time-point, regardless of whether they are in Hong Kong or not at the reference time-point.

3.6
The amount of time of stay in Hong Kong of "Mobile Residents" is less than that of the "Usual Residents". Nevertheless, the "Mobile Residents" have a close link with Hong Kong and most probably they have a regular residence in Hong Kong and utilize much of Hong Kong's facilities and services. In this regard, they should be considered as part of the Hong Kong Population.

3.7
Below is an illustration of the situations of different Mobile Residents:


(a) 


Persons staying 5 to 6 days each week in the mainland of China and staying regularly in Hong Kong during the weekends. As at mid-2001, there were some 56 300 such persons. They are mainly those working in the Mainland and returning to Hong Kong to stay with their families during the weekends.

(b) 
Persons staying for a major proportion of time in Mainland/Macao and returning to Hong Kong from time to time. There were some 75 100 such persons at mid-2001. Presumably they maintain residences in both Mainland/Macao and Hong Kong, and travel frequently between these places for business, work or family reasons.

(c) 
Elderly persons (aged 60 and over) staying for a major proportion of time in Mainland/Macao. There were some 8 300 such persons. Many of them have retired and settled in the Mainland but come back to Hong Kong frequently to visit children or relatives.

(d) 
Persons in school-attending age returning from overseas to stay in Hong Kong for several periods of time in a year. There were some 16 400 such persons. These are mainly Hong Kong students studying abroad and spending their vacations in Hong Kong.

(e) 
Besides, there are persons staying in overseas countries/territories but also staying frequently in Hong Kong for business, work or family reasons. There were some 26 500 such persons at mid-2001.

3.8
Chart 1 provides a diagrammatic presentation of the residency/mobility profiles.

3.9
As at mid-2001, there were a total of 182 600 "Mobile Residents". The above figures have been obtained through statistical processing of anonymised passenger movement data. The compilation procedures are conducted through computer processing, with all the personal data being anonymous and the identities kept strictly confidential.

3.10
Owing to the fact that the required data on passenger movement are not available for earlier dates, the estimates of the "Hong Kong Resident Population" in the statistical series are only provided in respect of reference time-points from 1996 onwards. Nevertheless, according to a comparison of major statistical indicators between the extended de facto population and the Hong Kong Resident Population in 1999, the differences of values between the two methods are relatively small, indicating that the pre-1996 series based on the old method could still be broadly analysed along with new series.


4.


Merits of the "resident population" method over the previously used "extended de facto" method


4.1
Under the "extended de facto" method, which has been used for compiling the series of population estimates up to 1995, a population base includes persons who are physically in Hong Kong as well as Hong Kong residents who are working in Mainland/Macao and those who are usually living in Hong Kong but in Mainland/Macao for short trips at the census moment, and are reported by family members in Hong Kong as such.

4.2
The revision to the method of compiling population estimates is made on account of the following limitations of the "extended de facto" method:

(a)
There has been an increasing trend for Hong Kong Permanent Residents to stay in the Mainland or Macao on a long-term basis for reasons of retirement, work or marriage. Also, a considerable number of Hong Kong residents are staying overseas for work, touring or studies. Applying the "de facto" method would lead to fluctuations in the population estimates and limit its ability to reflect the actual situation.

(b)
According to the "extended de facto" method, visitors to Hong Kong are included in the Hong Kong Population. But strictly speaking, visitors are not part of the Hong Kong Population.

(c)
The "extended de facto" method makes use of the difference between the number of arrivals and the number of departures. As those numbers are large, their difference may not be stable at times, especially around the commonly used reference time-points, e.g. end-June and end-December.


4.3
For more details of the "extended de facto" method and the related limitations, readers may refer to paragraphs 2.1-3.5 in the feature article entitled "Revision to the Method of Compiling Population Estimates of Hong Kong" published in the September 2000 issue of the Hong Kong Monthly Digest of Statistics.


4.4
In summary, the changing over to the "resident population" method for compiling population estimates of Hong Kong has taken the following into consideration:

(a) 
The application of the "resident population" method could better reflect the notable changes that have occurred in the residency and mobility patterns of the Hong Kong Population.

(b) 
Many countries and territories have changed over from the "de facto" method (i.e. the kind of method that was previously used in Hong Kong) to the "resident population" method for compiling population estimates. Hong Kong's adoption of the "resident population" method represents observance of the international trend.

(c) 
Using the "resident population" concept to measure the population size of a place is actually more relevant from the statistical theory standpoint. Its previous non-application was mainly due to limitations of insufficient data, e.g. statistical information based on passenger movement records. Also, in compiling various socio-economic statistical indicators (e.g. birth rate and death rate), the use of the "resident population" concept is generally more meaningful.

(d) 
The availability of enhanced computational capabilities of computers facilitates the handling of large volume of passenger movement data for the production of statistics required for the compilation process. This enables the computation of "resident population" figures at the reference time-points.


5.


Updating of population estimates and the release schedule


5.1
Under the "resident population" method for compiling population estimates, a population census/by-census continues to serve the benchmarking function. Updating of the population estimates to any new reference time-points is to draw upon the following main sources:

(a) 
Arrival and departure records of individual persons are linked for statistical computation (albeit the records are anonymised and un-identifiable to the individuals) for updating the estimate in respect of the Hong Kong Permanent Residents.

(b) 
For Hong Kong Non-permanent Residents, the method of computing the balance of arrivals over departures is continued to be used. Also, they are grouped under "Usual Residents". This is because for the duration that they hold that status of "Non-permanent Residents" they can be expected to be usually staying in Hong Kong.

(c) 
Statistical data compiled from other administrative systems such as birth and death records.

5.2
The application of the "resident population" method requires information on the amount of time of stay in Hong Kong of residents during the six months before and after the reference time-point. It follows that the population estimates could not be obtained within one or two months after the reference time-point.

5.3
In order to provide relevant figures as early as possible for use, the Census and Statistics Department will release "provisional estimates" for reference within two months after the reference time-point. Revised estimates will be released a further six months later.

5.4
That is to say, population estimates will be released every half-year, for the mid-year and year-end positions, by way of press release as in the past. For example, the provisional estimates for mid-2001 were released on 31 August 2001, while the revised estimates were released on 7 February 2002.

5.5
For the latest updating round of population estimates, the results recently obtained from the 2001 Population Census have been used as benchmarking data for establishing an updated population base. The updated population estimates are shown in Table 1.

5.6
Table 2 and Chart 2 present data series in respect of population estimates and population growth rates for 1971-2001 for ease of reference.


6.


Results of 2001 Population Census and Population Trend


6.1
Based on the results of the 2001 Population Census, the Hong Kong Resident Population at mid-March 2001 was 6.71 million. Among them, 6.52 million were Usual Residents and 0.18 million were Mobile Residents. Taking into account births, deaths, and movements of residents occurred during 14 March - 30 June 2001, the population as at mid-2001 was 6.72 million.

6.2
Referring to the population estimates at mid years, the population of Hong Kong increased from 4.04 million in 1971 to 6.72 million in 2001. The increase of 2.68 million constituted an average growth rate of 1.7% per annum. For some of the years in the early 1970's and early 1980's annual growth rates exceeded 2%. The high population growth in these years was mainly attributable to a high level of entrants from the mainland of China. For some years, the large increase in the number of Vietnamese migrants also contributed to the high population growth.

6.3
From the mid-1980's to early 1990's, population recorded rather low growth rate (e.g. 0.3% in the year 1990) mainly because of the large number of emigrants.

6.4
Population resumed high growth between 1993 and 1996, as many people who had emigrated in early years returned to Hong Kong. Thereafter, growth stablized while birth rate was in the meantime observed to be rather low.

Chart 1   Examples of residency/mobility profile of Mobile Residents

 

Table 1   Latest population estimates

   
HK Resident Population
Usual Residents
Mobile Residents
From the previous reference time-point to this reference time-point
Births
Deaths
Natural increase #
Net Movement (Inflow less outflow)
Mid-1996
6 435 500
6 242 800
192 700
-
-
-
-
Mid-1997
6 489 300
6 303 000
186 300
63 200
31 400
31 800
22 000
Mid-1998
6 543 700
6 361 800
181 900
55 100
32 300
22 800
31 600
Mid-1999
6 606 500
6 427 300
179 200
52 100
33 000
19 100
43 700
Mid-2000
6 665 000
6 481 800
183 200
51 100
34 200
16 900
41 600
Mid-2001
6 724 900
6 542 300
182 600
53 300
32 300
21 000
38 900
Notes: #  Natural increase = Births - Deaths

Table 2    Population growth since 1971

Year
Population estimate
at mid-year(1)

Growth rate compared
with the previous year
Year
Population estimate
at mid-year(1)
Growth rate compared
with the previous year
1971
4 045 300
2.2%
1987
5 580 500
1.0%
1972
4 123 600
1.9%
1988
5 627 600
0.8%
1973
4 241 600
2.9%
1989
5 686 200
1.0%
1974
4 377 800
3.2%
1990
5 704 500
0.3%
1975
4 461 600
1.9%
1991
5 752 000
0.8%
1976
4 518 000
1.3%
1992
5 800 500
0.8%
1977
4 583 700
1.5%
1993
5 901 000
1.7%
1978
4 667 500
1.8%
1994
6 035 400
2.3%
1979
4 929 700
5.6%
1995
6 156 100
2.0%
1980
5 063 100
2.7%
1996
6 435 500
2.5%(2)
1981
5 183 400
2.4%
1997
6 489 300
0.8%
1982
5 264 500
1.6%
1998
6 543 700
0.8%
1983
5 345 100
1.5%
1999
6 606 500
1.0%
1984
5 397 900
1.0%
2000
6 665 000
0.9%
1985
5 456 200
1.1%
2001
6 724 900
0.9%
1986
5 524 600
1.3%
   
  
  
Notes: 1)  The figures from 1971 to 1995 are compiled based on the "extended de facto" method and those from 1996 onwards are compiled based on the "resident population" method.
2)  The growth rate is compiled based on the mid-1996 population estimate of 6 311 000 under the "extended de facto" method.


Chart 2    Hong Kong Population Estimates, 1971-2001

Note: The figures from 1971 to 1995 are compiled based on the "extended de facto" method and those from 1996 onwards are compiled based on the "resident population" method.