Behind the PIPRICS calculator A detailed methodology for calculating planning assumptions for a priority infrastructure plan (PIP) using a regulated infrastructure charges schedule (RICS) 18 June 2008
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Department of Infrastructure and Planning Reply Paid 15009 City East Qld 4002 Australia telephone +61 (7) 3247 6273 email [email protected]
18 June 2008 © The State of Queensland (Department of Infrastructure and Planning) Copyright protects this publication. Except for purposes permitted by the Copyright Act 1968, no part may be produced by any means without the express prior permission of the Department of Infrastructure and Planning.
Introduction About this guide This guide is part of the PIPRICS package, which the Department of Infrastructure and Planning has developed to help local governments prepare a priority infrastructure plan (PIP) using the regulated infrastructure charges schedule (RICS).
The package comprises:
• the PIPRICS template
• a comprehensive user guide that explains each section of the template
• the PIPRICS calculator—an Excel-based file that automates much of the process for preparing planning assumptions
• this guide, which explains the detailed methodology behind the calculator.
As the PIPRICS calculator automates the preparation of planning assumptions (or growth projections), most local governments will not need to refer to this guide. However, it has been prepared as a courtesy for local governments interested in how the calculator works, or those wanting to refine it to suit their circumstances.
For further help with preparing priority infrastructure plans, refer to the Integrated Planning Act 1997 (IPA) and Infrastructure Guideline 1/04.
About the PIPRICS template The department recognises that if a local government is slower growing and wants to use regulated infrastructure charges, or not charge at all, it will require a less detailed and complex PIP. The PIPRICS template makes it possible for them to prepare one with much less effort, while still satisfying the requirements of the IPA. This plan will form part of their planning scheme, while the regulated infrastructure charges schedule will be an attachment to the planning scheme in compliance with section 5.1.16 of the IPA.
The PIPRICS template is not suitable for a priority infrastructure plan that includes an infrastructure charges schedule (ICS).
About the PIPRICS calculator The department developed the PIPRICS calculator to help local governments prepare planning assumptions for a priority infrastructure plan based on the regulated infrastructure charges schedule.
The PIPRICS calculator automates the calculation of growth projections for a local government area based on data provided by the Planning Information and Forecasting Unit (PIFU) and the Australian Bureau of Statistics (ABS).
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For step-by-step instructions on how to use the calculator, refer to page 24 of the PIPRICS user guide, How to use the PIPRICS template.
Contents Acronyms and abbreviations.............................................................................4
1. Population and housing projections.............................................................5
1.1 Projections of resident population and dwelling numbers ...............................5
Local government area ..............................................................................5
Inside the priority infrastructure area..........................................................7
Outside the priority infrastructure area .......................................................8
1.2 Projections of non-resident population and dwellings .....................................8
1.3 Total projections—resident plus non-resident population and dwellings.........9
2. Projections of employment and non-residential floor space....................10
2.1 ABS-based projections .................................................................................10
Local government area ............................................................................10
Inside the priority infrastructure area........................................................12
Outside the priority infrastructure area .....................................................13
2.2 Special development projections ..................................................................13
2.3 Total non-residential projections—ABS-based on projections plus special developments .....................................................................................................13
References ........................................................................................................14
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Acronyms and abbreviations ABS Australian Bureau of Statistics
AHS average household size
ERP estimated resident population
GFA gross floor area
ICS infrastructure charges schedule
IPA Integrated Planning Act 1997
LGA local government area
PEP place of enumeration profile
PIA priority infrastructure area
PIP priority infrastructure plan
PIFU Planning Information and Forecasting Unit
RICS regulated infrastructure charges schedule
1. Population and housing projections The following simplified methodology assumes that dwelling structure (distribution) will remain constant over the duration of the priority infrastructure plan (PIP), but makes it possible to take into account predicted changes in average household size in the local government area.
As infrastructure is required to service both residents and non-residents, the total dwelling and population projections for the local government area (presented in Table 2.1 of the PIP) are calculated as the sum of the projections for resident and non-resident populations (where they exist). The following sections outline how to do this.
1.1 Projections of resident population and dwelling numbers
Local government area a. Calculate the projected estimated resident population (ERP) for the local
government area at each point in time by applying the relevant data provided in the 06 low-, medium- or high-growth projections worksheets in the PIPRICS calculator, to the 2006 estimated resident population, provided on the Planning Information and Forecasting Unit (PIFU) fact sheet as follows:
2011 LGA ERP =
2006 LGA ERP (PIFU fact sheet) x (1+av. annual pop. growth rate 2006–11#)5
2016 LGA ERP =
2011 LGA ERP (PIFU fact sheet) x (1+av. annual pop. growth rate 2011–16#)5
2021 LGA ERP = LGA ERP (PIFU fact sheet) x (1+av. annual pop. growth rate 16–21#)5
# Average annual population growth rates should be in decimal form (i.e. 1% = 0.01).
See the LGA 06ERP & Growth worksheet in the calculator for the projection series that PIFU recommends for each local government area. (Note: Use the updated growth rates provided in the calculator, instead of those previously published in the PIFU fact sheets.)
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b. To calculate average household size for each type of private occupied
dwelling (single, multiple, other, all), and the average for all private occupied dwellings at each point in time, apply the average annual per cent change in average household size for the local government area shown in the LGA 06ERP & Growth worksheet in the calculator, to the 2006 averages for the local government area shown on the PIFU fact sheet as follows:
2011 AHS = 2006 AHS *(1+ av. annual per cent change in AHS#)5
2016 AHS = 2006 AHS *(1+ av. annual per cent change in AHS#)10
2021 AHS = 2006 AHS *(1+ av. annual per cent change in AHS#)15
#Average household size values should be in decimal form (i.e. 1% = 0.01).
c. Calculate the total number of dwellings required in the local government area at each point in time using the estimated resident population calculated in 1.1(a) and the average household size for all occupied private dwellings calculated in 1.1(b) as follows:
Total dwellings in LGA = Total estimated resident population in LGA (1.1a)
Average household size for all occupied private dwellings (1.1b)
d. Calculate the percentage distribution of occupied private dwellings in 2006 by dividing the total number of dwellings in each Australian Bureau of Statistics (ABS) dwelling classification by the total number of dwellings, as provided in the Place of Enumeration Profile (PEP) Table P-31 (Dwelling structure for all occupied private dwellings) for the local government area.
e. Calculate the sum percentage of dwellings for each PIP dwelling type (single dwelling, multiple dwelling, or other) in 2006, using the values calculated in 1.1(b) and relationships provided in Table 1. Table 1—Relationship between ABS dwelling classification and PIP dwelling type
ABS dwelling classification PIP dwelling type
Separate house Single dwelling
Semi-detached, row or terrace house, townhouse Multiple dwelling
Flat, unit or apartment Multiple dwelling
Other dwellings Other
Dwelling structure not stated Other
f. Determine the number of dwellings of each PIP dwelling type at each point in time as follows:
Number of dwellings = Total number of dwellings in LGA (1.1(c)) x percentage distribution (1.1(e))
g. Determine the population occupying each PIP dwelling type at each point in time using the projected local government area average household sizes for each type of dwelling calculated in 1.1(b).
Population = Number of dwellings (1.1(f)) x average household size (1.1(b))
h. Calculate the total population for the local government area at each point in time by summing the population occupying each PIP dwelling type (1.1(g)).
Inside the priority infrastructure area PIFU has used the 2006 census data (see the UCL 2006 ERP worksheet in the calculator) to approximate estimated resident population for all urban centres and rural localities in Queensland. In a local government area, these are typically the areas where there is development infrastructure, so they can be used to approximate the priority infrastructure area (PIA) in low-growth local government areas.
i. Calculate the 2006 population inside the PIA as the sum of the estimated resident population for all selected urban centres and rural localities or other defined areas within the local government area.
j. Use the relevant data on average annual population growth provided in the 06 low-, medium- or high-growth projections worksheets in the calculator to project forward the 2006 population inside the PIA as follows:
2011 PIA ERP = 2006 PIA ERP x (1+av. annual pop. growth rates 2006–11#)5
2016 PIA ERP = 2011 PIA ERP x (1+av. annual pop. growth rates 2011–16#)5
2021 PIA ERP = 2016 PIA ERP x (1+av. annual pop. growth rates 2016–21#)5
#Average annual population growth rates should be in decimal form (i.e. 1% = 0.01).
k. Repeat steps 1.1(a), 1.1(d), 1.1(e) and 1.1(f) to calculate the number of dwellings inside the PIA at each point in time, using the population inside the PIA calculated in 1.1(i) and (j) instead of the total population in the local government area. Users should note that they can use the PIPRICS calculator to change the distribution of residential growth between urban centres and rural localities inside and outside the PIA. For example, if the total projected growth in dwelling numbers in the local government area from 2006–21 is 1000
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dwellings, they can use the calculator to change the distribution of this total growth if certain areas are developing faster than others
Outside the priority infrastructure area l. Calculate resident population and housing projections for outside the PIA by
subtracting the total resident projections inside the PIA from the total for the entire local government area.
1.2 Projections of non-resident population and dwellings This methodology also caters for determining and including the non-resident population, which can also contribute to growth in areas that attract people whose permanent place of residence is outside the local government area. For example, mining areas where people fly in for work, or beachside areas where people visit second homes on weekends.
Where non-residents place a demand on trunk infrastructure, use local knowledge and information such as the number of development approvals that have been granted in previous years to estimate:
• the number of existing non-resident dwellings, by dwelling type, in each area of the local government area as at a specific base year
• the future growth in the number of these dwelling in each area of the LGA over each five-year period.
The following methodology assumes the average household sizes for non-resident dwellings are the same as those for resident (private occupied) dwellings as referenced in 1.1(b):
a. Estimate the current number of non-resident dwellings by dwelling type for each area within the local government area as at a specific base year.
b. Estimate the total growth in dwelling numbers by dwelling type for each area within the local government area, over each five-year period.
c. Calculate the total number of non-resident dwellings at the end of the period, by dwelling type, for each area, by adding the total growth projected for the preceding period (1.1(b)) to the total number of dwellings at the beginning of the period. For example:
Dwellings 2011 = Dwellings 2006 (1.2(a)) + total growth in dwellings 2006–11 (1.1(b))
d. Calculate the total non-resident population at each point in time, by dwelling
type, for each area, by multiplying the total number of dwellings 1.2(c) by the average household sizes referenced in 1.1(b).
Population = Number of dwellings (1.2(c)) x average household size (1.1(b))
1.3 Total projections—resident plus non-resident population and dwellings
a. Calculate the total population at each point in time for each dwelling type and area by adding the resident population calculated in 1.1, to the non-resident population calculated in 1.2.
b. Calculate the total dwellings at each point in time for each dwelling type and area by adding the resident dwellings calculated in 1.1, to the non-resident dwellings calculated in 1.2.
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2. Projections of employment and non-residential floor space Local governments can use this simplified methodology to prepare projections of employment and floor space. In accordance with current trends, the methodology assumes that employment will grow in line with predicted population growth. It should be noted that this methodology uses the ABS census and journey-to-work data.
2.1 ABS-based projections
Local government area a. Estimate the total number of jobs required in the local government area at
each point in time as follows:
LGA ERP x res. employment rate x labour force containment rate Total employment in LGA =
Job containment rate
Where:
• total projected estimated resident population in the local government area is calculated in Step 1.1(h)
• resident employment rate is calculated as follows using the ABS Census 2006 Basic Community Profile Tables B01a and B42c
Res. employment rate (%) = Number of persons employed (BCP Table B42c)
Total LGA population (BCP Table B01a)
• the labour force containment rate is the percentage of jobs within the local government area occupied by residents of that area
• the job containment rate is the percentage of residents’ jobs provided within the local government area.
The above containment rates are provided in Appendix C of the Population Growth—Highlights and Trends Qld 2005 report at www.localgovernment.qld.gov.au, which is included in the Employment containment rate worksheet in the calculator. Note that these containment rates are based on ABS census data for 2001, and the formula above assumes no significant change in employment patterns.
b. Look up the percentage employed in the local government area in 2006 in
each conversion category provided in the LGA Jobs by Non-Res Gross Floor Area (GFA) Cat. worksheet in the calculator. This is a customised table generated from ABS journey-to-work data based on place of work. It uses non-residential gross floor area conversion categories to represent the distribution of jobs provided in the local government area, using the relationships provided in Table 2. Non-residential gross floor area conversion categories include:
• retail
• commercial (e.g. office, personal services)
• industry
• community
• other (includes footloose and rural employment that does not apply to the PIA) such as agriculture, mining and construction).
Table 2—Relationship between non-residential GFA conversion categories and ABS industry classification
Industry classification Non-residential GFA conversion category
Agriculture, forestry and fishing Other
Mining Other
Manufacturing Industry
Electricity, gas, water and waste services Industry
Construction Other
Wholesale trade Industry
Retail trade Retail
Accommodation and food services Commercial
Transport, postal and warehousing Industry
Information media and telecommunications Commercial
Financial and insurance services Commercial
Rental, hiring and real estate services Commercial
Professional, scientific and technical services Commercial
Administrative and support services Commercial
Public administration and safety Commercial
Education and training Community
Health care and social assistance Commercial
Arts and recreation services Commercial
Other services including inadequately described/not stated
Other
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c. Determine employment numbers at each point in time for each conversion category.
No. employees =
Total employment LGA (2.1(a)) x percentage distribution in 2006 (2.1(b))
d. Determine the gross floor area (GFA) requirements at each point in time for each conversion category using either the general floor space conversion rates set out in Table 3, or local knowledge.
GFA, m2 = Number of employees (2.1(c)) x conversion rate (Table 3)
Table 3—Floor space conversion rates
Non-residential GFA conversion category
Conversion rate (m2
GFA/employee)
Commercial 20
Retail 25
Industry 70–150 (110)*
Community N/A
Other N/A
* Use 70 m2/employee where industry is predominantly light/service industry. Use 150 m2/employee for transport, storage and warehouses. Alternatively, use an average of 110 m2/employee.
e. Calculate the total floor space (m2 GFA) requirements for the local government area at each point in time by summing the floor space required for each conversion category (2.1(d)).
Inside the priority infrastructure area f. Estimate the total employment inside the PIA for each conversion category
(excluding ‘Other’) at each point in time from the above local government area employment projections as follows:
Employment inside PIA= Population inside the PIA (1.1(j)) x employment in LGA (2.1(a))
LGA population (1.1(h))
Note: All employment in the ‘Other’ category is assumed to be outside the PIA; therefore, ‘Other’ employment is equal to zero inside the PIA.
g. Repeat steps 2.1(d) and 2.1(e) to calculate floor space requirements inside the PIA at each point in time using the employment numbers calculated in 2.1(f) instead of those in the local government area.
Outside the priority infrastructure area h. Calculate projections for employment outside the PIA for each conversion
category by subtracting the employment projections inside the PIA (2.1(f)) from those for the entire LGA (2.1(c)). Note: Assign all employment in the ‘Other’ category to outside the PIA.
i. Repeat 2.1(d) and (e) to calculate floor space requirements for outside the PIA using the employment numbers calculated in 2.1(h).
2.2 Special development projections Non-residents and other economic factors that cannot be predicted using historical data can also influence growth projections in non-residential areas (e.g. tourist development or an unanticipated industrial development in an area).
Use the following methodology to take account of special developments (inside or outside the PIA):
a. Estimate the growth in floor space attributable to special developments in the commercial, retail and industrial development categories for each area over each time period.
b. Estimate the number of employees attributable to special developments in the community development category for each area over each time period.
c. Using the conversion rates in Table 3, convert the amount of floor space at each point in time for each development type and area into number of employees. No conversion is required for the community development category.
2.3 Total non-residential projections—ABS-based projections plus special developments
a. Calculate the total number of employees at each point in time for each development type and area (inside and outside the PIA, and the total in the local government area) by adding the number of employees calculated in 2.1, to the number calculated in 2.2.
b. Calculate the total floor space at each point in time for each development type and area (inside and outside the PIA, and the total in the local government area) by adding the floor space in 2.1, to the floor space in 2.2.
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References The methodologies use the following information:
• Population and housing fact sheets produced by the Planning Information and Forecasting Unit (PIFU) of the Department of Infrastructure and Planning (Queensland).
• Annual population growth data and average annual change in average household size data as provided by PIFU (PIPRICS calculator).
• ABS 2006 Census Basic Community Profile (BCP) and Place of Emuneration Profile (PEP) for the local government area found at www.abs.gov.au.
• 2006 ERP for all urban centres and rural localities (UCLs) in Queensland and a list of all census collector districts that comprise the UCLs as prepared by PIFU (PIPRICS calculator).
• Appendix C of the Population Growth—Highlights and Trends Queensland 2005 report (PIPRICS calculator)
• 2006 Jobs in LGA by Non-residential GFA Conversion Category prepared by PIFU based on ABS Census 2006 data (PIPRICS calculator).
