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| New York City Housing and Vacancy Survey (NYCHVS) |
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To ensure the confidentiality of the data on the microdata files, all financial characteristics that are not calculated variables have been topcoded which greatly reduces the chances of an individual or a household being identified. The number of cases that need to be topcoded for each characteristic is equal to either ½ of 1 percent of the total universe, or 3 percent of all reporting cases, whichever is less. In addition, age was topcoded to 90 years, stories in structure and floor of unit were topcoded at 21 floors, and units in structure was topcoded at 100 units.
Topcoding was done differently in 1991 and 1993 than in 1996 and 1999. In 1991, the method of presentation shows the actual topcode value for each of the cases above the topcode. For example, contract rent was topcoded to $2,200. All contract rent amounts less than $2,200 are shown as reported. All amounts reported at $2,200 or more are shown as $2,200.
In 1993, the median for the cases above the topcode is shown. For example, the topcode for mortgage payment is $4,200. If the number of cases above $4,200 is 15, the median is calculated based on those 15 cases, and that value appears on the data file for each case above $4,200.
In 1996 and 1999, the mean value for all cases falling above the topcode value was calculated and then assigned to each individual case. For example, in 1999 approximately ½ of 1 percent of the renter-occupied units had a contract rent above $2,950. The mean contract rent for these cases is calculated to be $3,817 and is assigned to each case falling above the topcode. The topcodes for 1999 are calculated in the same manner as those for 1996.
For calculated variables such as contract rent per room, contract rent as a percent of income, gross rent per room, and gross rent as a percent of income, cases with values above the topcode amounts are included in the not-computed category.
A list of the items topcoded and the topcode value are shown on the following pages.
| Item | Topcode Value* | |||
|---|---|---|---|---|
| 1999 | 1996 | 1993 | 1991 | |
| Age | 90 years | 90 years | 90 years | 90 years |
| Asking Rent | $2,500 | $1,400 | $2,000 | $2,199 |
| Down Payment | $180,000 | $200,000 | $195,000 | $349,999 |
| Monthly Condominium or Maintenance Fees | $2,500 | $2,500 | $2,500 | $2,499 |
| Monthly Contract Rent | $2,950 | $2,500 | $2,200 | $2,199 |
| Monthly Rent - Previous Residence | N/A | $1,700 | $2,200 | $2,199 |
| Monthly Cost of Electricity | $240 | $250 | $200 | $199 |
| Monthly Cost of Gas | $390 | $500 | $350 | $499 |
| Monthly Cost of Gas and Electricity Combined | $290 | $300 | $280 | $499 |
| Monthly Mortgage Payment | $2,800 | $2,600 | $4,200 | $4,199 |
| Number of Stories/Floor of Unit | 21 | 21 | 21 | 21 |
| Units in Structure | 100 | 100 | 200 | 200 |
| Person Income From: | ||||
| Wages, Salary, Commissions, etc. | $160,000 | $140,000 | $140,000 | $100,000 |
| Farm or Nonfarm Business, etc. | $120,000 | $140,000 | $150,000 | $100,000 |
| Interest, Dividends, Royalties, etc. | $36,000 | $30,000 | $50,000 | $100,000 |
| Social Security or Railroad Retirement | $17,401 | $17,000 | $14,000 | $100,000 |
| SSI, AFDC, Home Relief, or other Public Assistance Payments | $10,801 | $10,500 | $10,000 | $100,000 |
| Retirements, Survivor, or Disability Pensions | $41,601 | $34,300 | $30,000 | $100,000 |
| VA Payments, Unemployment, Child Support, Alimony, or Other Income Sources | $17,501 | $22,000 | $15,000 | $100,000 |
| Item | Topcode Value* | |||
|---|---|---|---|---|
| 1999 | 1996 | 1993 | 1991 | |
| Purchase Price | $500,000 | $480,000 | $750,000 | $749,999 |
| Value | $730,000 | $750,000 | $1,000,000 | $999,999 |
| Year Built | 1990 | 1980 | 1980 | 1980 |
| Yearly Cost of Other Fuels | $3,840 | $4,000 | $6,000 | $5,999 |
| Yearly Cost of Water and Sewer | $828 | $900 | $900 | $899 |
| Fire and Liability Insurance | $1,900 | $2,000 | $1,700 | $2,999 |
| Real Estate Taxes | $7,500 | $7,500 | $7,500 | $7,499 |
