2006 ACS and PRCS Minimum and Maximum Codes
The following eleven housing variables and seven person variables are top-coded in the 2006 American Community Survey and Puerto Rican Community Survey Public Use Microdata Sample files:
|Housing Variables||IPUMS Variables||Person Variables||IPUMS Variables|
|Electricity (monthly cost) - ELEP (top-coded)||COSTELEC||Wages or salary income last year - WAGP (top-coded)||INCWAGE|
|Gas (monthly cost) - GASP (top-coded)||COSTGAS||Self-employment income last year (signed) - SEMP (top-coded and bottom-coded)||INCBUS00|
|Water (yearly cost) - WATP (top-coded)||COSTWATR||Interest, dividends, and net rental income last year (signed) - INTP (top-coded and bottom-coded)||INCINVST|
|House Heating fuel (yearly cost) - FULP (top-coded)||COSTFUEL||Retirement income last year - RETP (top-coded)||INCRETIR|
|Condo fee (monthly amount) - CONP (top-coded)||CONDOFEE||All other income last year - OIP (top-coded)||INCOTHER|
|Monthly rent - RNTP (top-coded)||RENT||Age - AGEP (top-coded)||AGE|
|Property taxes (yearly amount) - TAXP (top-coded)||PROPTX99||Travel time to work - JWMNP (top-coded)||TRANTIME|
|Fire/hazard/flood insurance (yearly amount) - INSP (top-coded)||PROPINSR|
|Mortgage payment (monthly amount) - MRGP (top-coded)||MORTAMT1|
|Second mortgage payment (monthly amount) - SMP (top-coded)||MORTAMT2|
|Mobile home costs (yearly amount) - MHP (top-coded)||MOBLHOME|
The Census Bureau derived its top-codes and bottom-codes based on the following rules:
- Age, travel time to work, and all base dollar amounts are top-coded using the state mean of all cases greater than or equal to the top-code state minimum value. The only exception to the top-code state minimum value is TAX, which uses the top-code national minimum value. Income amounts which can have negative values (SEMP and INTP) are bottom-coded using the state mean of all cases less than or equal to the bottom-code state maximum value. Recodes of dollar amounts use the rounded top-coded/bottom-coded base dollar amounts without any additional top-coding/bottom-coding.
- Top-coded property taxes are further assigned to one of 68 categories.
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 top-codes 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 2006 ACS/PRCS files are available here (.xls).