2000 American Community Survey Minimum and Maximum Codes

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The following eleven housing variables and nine person variables are top-coded in the 2000 American Community Survey Public Use Microdata Sample files:


Housing Variables IPUMS Variables Person Variables IPUMS Variables
Electricity (monthly cost) - ELEP COSTELEC Wages or salary income last year - WAGP INCWAGE
Gas (monthly cost) - GASP COSTGAS Self-employment income last year (signed) - SEMP INCBUS00
Water (yearly cost) - WATP COSTWATR Interest, dividends, and net rental income last year (signed) - INTP INCINVST
House Heating fuel (yearly cost) - FULP COSTFUEL Social security income last year - SSP INCSS
Condo fee (monthly amount) - CONP CONDOFEE Supplementary Security Income last year - SSIP INCSUPP
Monthly rent - RNTP RENT Public assistance income last year - PAP INCWELFR
Property taxes (yearly amount) - TAXP PROPTX99 Retirement income last year - RETP INCRETIR
Fire/hazard/flood insurance (yearly amount) - INSP PROPINSR All other income last year - OIP INCOTHER
Mortgage payment (monthly amount) - MRGP MORTAMT1 Age - AGEP AGE
Second mortgage payment (monthly amount) - SMP MORTAMT2
Mobile home costs (yearly amount) - MHP MOBLHOME


The Census Bureau derived its top-codes based on the following rules:

  1. Within each state, all base dollar amounts are top-coded using the mean of all cases greater than the top-code national minimum value.
  2. The maximum bottom-coding value for all component income dollar amounts which can be negative is $10,000.
  3. Recodes of dollar amounts use the rounded top-coded or bottom-coded base dollar amounts without any additional top-coding or bottom-coding.
  4. Top-coded property taxes are further assigned to one of 68 categories.
  5. AGE is top-coded using the state mean of all cases greater than 90.

The top-codes listed below reflect the IPUMS data. Users should be aware that the IPUMS top-codes diverge from the top-codes listed in the Census Bureau's documentation for two main reasons:

  • The Census Bureau rounds its top-coded values before releasing the public-use data. For example, wage and salary income is rounded to the nearest $1,000 such that an actual top-coded value of $158,333 would become $158,000 in the public-use data. In most cases, these top-codes are off by no more than 0.1% from what would have been obtained if the Census Bureau had released the original, non-rounded top-codes. Monthly electricity and gas costs variables are rounded to the nearest $10. Because IPUMS multiplies these amounts by 12 to obtain the annual electricity and gas costs, this rounding error is similarly multiplied by 12. Still, most IPUMS utility top-codes diverge from the non-rounded utility topcodes by no more than 1%.
  • While the Census Bureau documents top-codes for property taxes as actual dollar amounts, the public-use version of this variable is collapsed into sixty-nine categories. Similarly, the number of minutes one takes to get to work is documented as a three-digit variable, but is released only as a two-digit variable.


The top-codes and bottom-codes for the 2000 ACS file are available here (.xls).



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