ACS 2005 Standard Quality Rent Calculation for
Alcorn County, MS

The following information provides details on how the 2005 ACS Standard Quality Median Rent of $507 and the 2000 Census Standard Quality Median Rent of $446 and the update factor of 1.1368 was developed for Alcorn County, MS using the publically releasable distributions for Mississippi.

The distributions shown below are constructed by removing the counts of ACS-1 and ACS-2 areas from the total state distributions.

User Note

In computing state based standard qualtiy rents, HUD actually uses data on rent distributions that are prohibited from public release under Title XIII to protect the confidentiality of respondents. The distributions used in this demonstration are rounded versions of the actual, protected data.

The rounding scheme is as follows:

0, count = 0
1 to 7, count = 4
all other counts are rounded to the nearest 5 (e.g., 10, 15, 20, 25, etc.)

CALCULATIONS USING THE ROUNDED DATA MAY NOT PRODUCE THE SAME RESULT AS CALCULATIONS USING THE PROTECTED DATA. THE DIFFERENCE BETWEEN HUD'S ACTUAL RESULTS AND THOSE DEMONSTRATED HERE IS INVERSELY RELATED TO THE SIZE OF THE AREA. THAT IS, THE LARGER THE AREA, THE CLOSER THE CALCULATION BASED ON THE ROUNDED DATA IS LIKELY TO BE TO THE CENSUS BASE RENT COMPUTED FROM THE PROTECTED DATA.


Standard Quality Rents

HUD uses rents for standard quality units to generate update factors. "Standard Quality" units and rents are determined by limiting the full Census sample by including only responses meeting the following criteria:

a. Occupied rental units paying cash rent
b. Specified renter ? on 10 acres or less
c. with full plumbing
d. with full kitchen
e. built before 1999
f. meals not included in rent

Neither the 2000 Census not the 2005 ACS included a question that could be used to filter public or assisted housing from the rental distributions, however HUD is required to ensure that FMRs exclude non-market rental housing in their computation. Therefore, HUD excludes all units falling below a specified rent level determined from public housing rents in HUD's program databases as likely to be either assisted housing or otherwise at a below-market rent (perhaps due to quality problems not otherwise captured by the survey questions).

The "public housing" rent cut-off in Mississippi in 2005 is $222 and the 2000 cut-off rent is $213.

A Microsoft Excel file containing the unsummarized versions of the publicly releasable standard quality 2-bedroom rent distributions from the 2005 ACS for Mississippi, excluding ACS-1 and ACS-2 areas, is available here.

A Microsoft Excel file containing the unsummarized versions of the publicly releasable standard quality 2-bedroom rent distributions from the 2000 Census for Mississippi, excluding ACS-1 and ACS-2 areas, is available here.


50th Percentile 2005 ACS Standard Quality Rent - Mississippi

The following table and calculations demonstrate how the 50th percentile 2005 ACS standard quality rent is determined for Mississippi using the public distribution of standard quality rents for the state.

Portion of Standard Quality Rent Distribution Gross Rent Dollar Range Number of Units Percent of Eligible Distribution Cumulative Percent
Units below interval containing
public housing rent level of $222
$0 to $199 6,889 Not in Distribution Not in Distribution
Units in interval containing
public housing rent level of $222
$200 to $221 1,047.20 Not in Distribution Not in Distribution
$222 to $224 142.80 0.2% 0.2%
Units below interval containing
50th percentile standard quality rent of $506
$225 to $499 38,775 48.3% 48.5%
Units in interval containing
50th percentile standard quality rent of $506
$500 to $524 4,720 5.9% 54.4%
Units above interval containing
50th percentile standard quality rent of $506
$525 or more 36,645 45.6% 100.0%
Total Units Above Public Housing Rent in Standard Quality Rent Distribution   80,282.80    

The numbers of units with standard quality rents above and below the Public Housing Rent level of $222 for Mississippi are determined using linear interpolation over the 1,190 units in the rent range $200 to $224. Linear interpolation uses the assupmtion that the 1,190 units' rents are uniformly distributed in the rent range around the Public Housing Rent level. Under this assumption, the proportion of the rent interval ($25) that is below the Public Housing Rent level is the same as the proportion of units with rents in the interval (1,190) that have rents below the Public Housing Rent level.

Proportion of rent interval below the Public Housing Rent Level: ($222 - $200) / $25 = 0.8800

Units in the Public Housing Rent Level Interval below the Public Housing Rent Level: 0.8800 x 1,190 = 1,047.20

The 50th percentile standard quality rent for Mississippi is computed by linear interpolation over the 4,720 units in the rent range $500 to $524. Linear interpolation uses the assupmtion that the 4,720 units' rents are uniformly distributed in the rent range around the 50th percentile. Under this assumption, the proportion of the rent interval ($25) that needs to be added to the lower limit of the interval to reach the 50th percentile rent is the same as the proportion of units in the interval that needs to be added to the units in lower rent intervals to reach 50 percent of units in the distribution.

50 percent of units = 0.5 x 80,282.80 = 40,141.40

Units below the 50th percentile rent interval = 38,775.00 + 142.80 = 38,917.80

Units in 50th percentile rent interval needed to reach 50 percent of units = 40,141.40 - 38,918 = 1,223.60

Additional Units as Proportion of Interval = 1,223.60 / 4,720 = 0.2592

Dollars Added to Lower Limit of Interval to reach 50th percentile rent = 0.2592 x $25 = $6

50th percentile standard quality rent = $500 + $6 = $506

The difference between the actual 2005 ACS Standard Quality Rent of $507 and the demonstration 2005 ACS Standard Quality Rent of $506 computed here is due to the effects of rounding on the public distribution as described above.


50th Percentile Standard Quality Rent - Mississippi

The following table and calculations demonstrate how the 50th percentile Census 2000 standard quality rent is determined for Mississippi using the public distribution of standard quality rents for the state.

Portion of Standard Quality Rent Distribution Gross Rent Dollar Range Number of Units Percent of Eligible Distribution Cumulative Percent
Units below interval containing
public housing rent level of $213
$1 to $199 8,133 Not in Distribution Not in Distribution
Units in interval containing
public housing rent level of $213
$200 to $212 997.36 Not in Distribution Not in Distribution
$213 to $224 920.64 1.4% 1.4%
Units below interval containing
50th percentile standard quality rent of $447
$225 to $424 28,754 43.4% 44.8%
Units in interval containing
50th percentile standard quality rent of $447
$425 to $449 3,891 5.9% 50.7%
Units above interval containing
50th percentile standard quality rent of $447
$450 or more 32,660 49.3% 100.0%
Total Units Above Public Housing Rent in Standard Quality Rent Distribution   66,225.64    

The numbers of units with standard quality rents above and below the Public Housing Rent level of $213 for Mississippi are determined using linear interpolation over the 1,918 units in the rent range $200 to $224. Linear interpolation uses the assupmtion that the 1,918 units' rents are uniformly distributed in the rent range around the Public Housing Rent level. Under this assumption, the proportion of the rent interval ($25) that is below the Public Housing Rent level is the same as the proportion of units with rents in the interval (1,918) that have rents below the Public Housing Rent level.

Proportion of rent interval below the Public Housing Rent Level: ($213 - $200) / $25 = 0.5200

Units in the Public Housing Rent Level Interval below the Public Housing Rent Level: 0.5200 x 1,918 = 997.36

The 50th percentile standard quality rent for Mississippi is computed by linear interpolation over the 3,891 units in the rent range $425 to $449. Linear interpolation uses the assupmtion that the 3,891 units' rents are uniformly distributed in the rent range around the 50th percentile. Under this assumption, the proportion of the rent interval ($25) that needs to be added to the lower limit of the interval to reach the 50th percentile rent is the same as the proportion of units in the interval that needs to be added to the units in lower rent intervals to reach 50 percent of units in the distribution.

50 percent of units = 0.5 x 66,225.64 = 33,112.82

Units below the 50th percentile rent interval = 28,754.00 + 920.64 = 29,674.64

Units in 50th percentile rent interval needed to reach 50 percent of units = 33,112.82 - 29,675 = 3,438.18

Additional Units as Proportion of Interval = 3,438.18 / 3,891 = 0.8836

Dollars Added to Lower Limit of Interval to reach 50th percentile rent = 0.8836 x $25 = $22

50th percentile standard quality rent = $425 + $22 = $447

The difference between the actual 2000 Census Standard Quality Rent of $446 and the demonstration 2000 Census Standard Quality Rent of $447 computed here is due to the effects of rounding on the public distribution as described above.


Computing the 2000 - 2005 State Standard Quality Update Factor - Alcorn County, MS

The 2000 to 2005 update factor is calculated as the ratio of the 2005 ACS standard quality median rent to the 2000 Cesus standard quality median rent for Mississippi. Therefore the 2000 - 2005 update factor is:

= 2005 Standard Quality Median Rent / 2000 Standard Quality Median Rent

= $506 / $447

= 1.132

The difference between the actual 2000 - 2005 update factor of 1.1368 and the demonstration update factor of 1.132 computed here is due to the effects of computational rounding and the use of the rounding performed on the public distributions as described above.



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Problems or questions? Contact Peter.B.Kahn@hud.gov.