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Contributor/author(s): Kyle D.J.

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Supply and Demand

The economic supply and demand in your city involves interaction of the following 7 parameters:

1. Residential (Res) -- These are residents in your city (i.e., population).
2. Commercial (Com) -- These are commercial activities in your city (i.e., commercial "population").
3. Industrial (Ind) -- These are industrial activities in your city (i.e., industrial "population").
4. Recreation (Recr) -- These are things for your residents to do when they are not working (i.e., activities).
5. Commercial Connections (Com CX) -- These are commercial relations with the economy outside of your city (i.e., trade).
6. Industrial Connections (Ind CX) -- These are industrial relations with
   the economy outside of your city (i.e., import/export).
7. Workforce (Work) -- These are jobs created in your city for your residents (i.e., employment).

These interactions are shown in the picture below:

Available employment (Work) attracts residents (Res). These residents demand recreation (Recr). The employment is created by commerce (Com) and industry (Ind). Commerce and industry also demand connections (Com CX and Ind CX) to the rest of SimNation.

The items built in your city influence supply and demand as shown in the following table:

Supplies         Demands                Item
~~~~~~~~         ~~~~~~~                ~~~~

Rewards

128000 Recr      256 Work               Amusement Park
  9000 Recr       36 Work               City Hall
 37500 Recr       75 Work               Country Club
 --              135 Work               Courthouse
  1750 Ind       500 Work               Defence Contractor
 25000 Recr       50 Work               Geyser Park
 10000 Recr        1 Work               Historic Statue
  6000 Recr        8 Work               Lighthouse
  6000 Recr        4 Work               Mayor's House
 --              135 Work               Medical Research Centre
  2000 Res      1000 Work               Military Base
 48000 Recr       40 Work               Performing Arts Centre
 --              375 Work               Science Centre
125000 Recr      200 Work               Stadium
   480 Com       480 Work               Stock Exchange
 --              500 Work               University

750000 Recr,     250 Work               Spaceport
750000 Ind CX,
750000 Com CX

Business Opportunities

 --              225 Work               Maximum Security Prison
  1750 Ind       250 Work               Toxic Waste Conversion Plant

 75000 Recr,     250 Work               Casino Row
   750 Com

 25000 Recr,     250 Work               Gigamall
  1250 Com

Transportation

 --                2 Work               Bus Station
 --                2 Work               Subway Station
 --                2 Work               Subway-to-Rail Station
 --                4 Work               Train Station
 25000 Ind CX        --                 Rail neighbour connections
 25000 Com CX        --                 Subway neighbour connections

 20000 Com CX,       --                 Highway neighbour connections
 14000 Ind CX

 12000 Com CX,       --                 Road neighbour connections
 12000 Ind CX

Civic Services

 --               45 Work               City College
 --               45 Work               City Jail
 --               45 Work               Fire Station
 --               45 Work               Hospital
  7000 Recr       20 Work               Library
  9000 Recr       45 Work               Museum
 --               45 Work               Police Station
 --               45 Work               School

Entertainment

  4000 Recr       16 Work               Ballpark
  2250 Recr        9 Work               Big Park
 24000 Recr       48 Work               City Zoo
   250 Recr        1 Work               Fountain
  9000 Recr       18 Work               Marina
  1000 Recr        4 Work               Playground
  1000 Recr        4 Work               Pond
   250 Recr        1 Work               Small Park

Utilities

 --               36 Work               Desalinization Plant
 --               18 Work               Incinerator
 --               18 Work               Recycling Centre
 --               18 Work               Waste-to-Energy Incinerator
 --               16 Work               Water Treatment Plant

Power Plants

 --               48 Work               Coal Power Plant
 --               48 Work               Fusion Power Plant
 --               48 Work               Gas Power Plant
 --               48 Work               Microwave Power Plant
 --               96 Work               Nuclear Power Plant
 --               48 Work               Oil Power Plant
 --               32 Work               Solar Power Collector

Zones (effects are per tile)

    23 Res        22 Recr               LD LLV Res
    19 Res        20 Recr               LD MLV Res
    18 Res        18 Recr               LD HLV Res
    73 Res        73 Recr               MD LLV Res
    71 Res        70 Recr               MD MLV Res
    67 Res        67 Recr               MD HLV Res
   157 Res       157 Recr               HD LLV Res
   151 Res       150 Recr               HD MLV Res
   147 Res       142 Recr               HD HLV Res
    20 Res        10 Recr               Generic Res

    18 Com        17 Work,  18 Com CX   LD LMLV Com
    17 Com        16 Work,  17 Com CX   LD MHLV Com
    64 Com        59 Work,  64 Com CX   MD LMLV Com
    61 Com        57 Work,  61 Com CX   MD MHLV Com
   130 Com       123 Work, 130 Com CX   HD LMLV Com
   128 com       117 Work, 128 Com CX   HD MHLV Com
    19 Com        19 Work,  19 Com CX   Generic Com

    19 Ind        17 Work,  20 Ind CX   LD Dirty Ind
    67 Ind        61 Work,  67 Ind CX   MD Dirty Ind
   130 Ind       127 Work, 130 Ind CX   HD Dirty Ind
    17 Ind        17 Work,  17 Ind CX   LD Clean Ind
    61 Ind        59 Work,  61 Ind CX   MD Clean Ind
   129 Ind       123 Work, 129 Ind CX   HD Clean Ind
    11 Ind        11 Work,  11 Ind CX   Generic Ind
    11 Ind        10 Work,  11 Ind CX   Agriculture

   100 Ind CX,     5 Work               Airport
   500 Com CX

   250 Ind CX,     5 Work               Seaport
   100 Com CX

LD = Low Density
MD = Medium Density
HD = High Density
LLV = Low Land Value
MLV = Medium Land Value
HLV = High Land Value
LMLV = Low/Medium Land Value
MHLV = Medium/High Land Value
"Generic" tiles are under construction, accumulating garbage, 
or abandoned.

Examples from the table:

1. The Courthouse reward doesn't supply anything, but demands 135 workers.
2. The Spaceport reward supplies 750 000 of each of recreation, commercial connections and industrial connections, and it demands 250 workers.
3. A road connection to a neighbouring city provides 12 000 of each of commercial and industrial connections, and doesn't demand anything.
4. A single tile of low-density residential zone with low land value provides 23 residents and demands 22 recreation.
5. A single farm tile (agriculture) provides 11 industry, and demands 10 workers and 11 industrial connections.

Every city also starts with a base amount of economic connections.  These represent connections provided from outside the city that are beyond your control. These drive your economy when your city is small.  They are:

25000   Recreation (Recr)
25000   Commercial Connections (Com CX)
70000   Industrial Connections (Ind CX)

(As you can see the city starts with a stronger demand for industry than commerce.)

As your city grows it will use this initial supply/demand to survive.  But once they are all used up you will need to add more to continue growth.  For example, the initial 25000 recreation will support about 25000 residents.  To grow beyond this you need to increase the supply of recreation in your city by building suitable recreation items, as listed in the large table above.  (This is often called "raising or relieving a demand cap".)

Employment

Each job in the city attracts 2 residents. (Think of it this way: each Sim that moves to your city to find work brings with them on average one other person who does not work, e.g., spouse, child, relative, etc.)  So if for example you want your city to grow to a population of 2 million, then you will need 1 million jobs available.  The large table above shows how you can create these jobs.

There are always 150 Sims looking for work in your city, but not living in your city (meaning they commute in). The simulation uses these commuters to help start a new city when population and industry are very small.  However once the city starts growing, the importance of these external workers very rapidly becomes negligible.  For example when your population is 3000 (so 1500 workers), then you have 10 times as many workers living in your city as commute in.

Economic Phases

When population is low, it is the city's industry that employs most of the residents. As population increases, a greater percentage of Sims will find work in commerce instead of industry. The following chart shows the required distribution of commerce and industry based on population. The zoning in your city should evolve to suit the trends in this chart:

To estimate the commerce and industry percentages in your city, use the game's graph feature to display the data for commerce and industry.  The numbers at the right of that graph are the commercial and industrial sector sizes.  Compare these two numbers to determine the percentage distribution between them in your city.  Then compare your city's percentage to the required percentage on the chart above (for your current residential population) to determine if you should adjust your zoning distribution.

"Major events" influence the larger economy of SimNation, and this affects the residential demand within your city. These events are hard-coded into the game to occur at predetermined times.  There is nothing you can do to change these events. But knowing when they occur can help explain why the residential demand plummets sometimes. The effect and duration of these major events are shown in the table below. Also shown is the game year assuming a starting year of 1900.

Duration   Year   Influence
[years]             [%]
~~~~~~~~   ~~~~   ~~~~~~~~~
 27        1900      0
  3        1927    - 5
 13        1930      0
  2        1943    -90
 14        1945      0
  6        1959    -10
 20        1965      0
  2        1985    -50
  3        1987    + 5
 18        1990      0
  2        2008    -90
 22        2010      0
  4        2032    -20
  4        2036    +10
 10        2040      0
           2050	

These fluctuations appear to be partly modelled after the historical economy of the USA. For example, the Great Depression appears as an influence of -5% between 1927 and 1930, and World War II appears as -90% between 1943 and 1945.

After 2050 (again assuming a start of 1900) the cycle keeps repeating itself:

Duration   Year   Influence
~~~~~~~~   ~~~~   ~~~~~~~~~
 27        2050      0
  3        2077    - 5
 13        2080      0
  2        2093    -90
 14        2095      0
...etc.

Effect of Taxation on RCI Demand

The RCI tax rates affect demand (and thus growth potential) for their respective zones. For any given population there is a "neutral" tax rate which has no effect upon demand. If the tax rate is set lower than this neutral rate, then demand will be increased (encourages growth). If the tax rate is set higher than the neutral rate, then demand will be decreased (encourages decline). So there is a trade-off between tax revenues and zone demand. These trends are shown in the following chart:

Note that above 320 000 population there is no further change. At the higher populations there is virtually no growth benefit due to low taxes, and high taxes carry a huge demand penalty. Keeping tax rates set equal to the neutral tax rate may be the best strategy. The trends for neutral tax rate versus population are shown in the following chart:

Again, these are the RCI tax rates which will have no effect upon demand.  There is no further change above 320 000 population (i.e., the neutral tax rate remains 5%).

Effect of Ordinances on Demand

The following ordinances influence the demand for commerce and industry:

Tourist Promotion          +15% Com & -1.5% Ind
Water Conservation          -3% Ind
Power Conservation          -3% Ind
Industrial Waste Disposal   -2% Com & -8.5% Ind

See also
RCI building density table
RCI building density table (detailed)
Land value vs. density tables
Bonds, Taxes, and Neighbour Deals

Knowledge Tree
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