Calculating The Estimates And Weights For The Vacancy Rate

Prepared for the 2010

SDC-CIC Joint Steering Committee Meetings

February 24, 2010

Edward C. Castro Jr.U.S. CENSUS BUREAU

U.S. DEPARTMENT OF COMMERCE

Washington, DC 20233

2

Outline

• Weighting

• Distribution of Vacant and Occupied Housing Units

• Vacancy Rate

• Summary

3

Weighting

• Weights account for sampling the population.

• Initial weight accounts for probability of selection. Non-respondents for mail and telephone are sampled for follow-up.

• Non-interview adjustments controlled by geography, sample month, and type of home.

• Controls are applied to housing unit and population totals to correct coverage error.

4

Distribution of Vacant and Occupied Housing Units

Weighting Step Distribution

Initial weight and non-respondents

Vacant Housing Units

Non-interviews

Occupied Housing Units

Non-interview Adjustment

Vacant Housing Units

Occupied Housing Units including Non-interviews

Housing Unit Controls

Vacant Housing Units

Occupied Housing Units including Non-interviews

5

Vacancy Rate

Vacant Housing Units

Non-interviews

Occupied Housing Units

Initial weight and non-respondents

8,000* 2,000 40,000

Non-interview Adjustment

8,000

Adjustment =

(40,000 + 2,000) / 40,000 =

1.05

40,000 x 1.05 =

42,000

* Initial Vacancy Rate = 8,000 / 50,000 = 16%

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Vacancy Rate (cont.)

Vacant Housing Units

Occupied Housing Units

Non-interview Adjustment

8,000 42,000

Housing Unit Controls

Total Housing Units = 50,000

Housing Unit Control = 51,500

Adjustment = 51,500 / 50,000= 1.03

8,000 x 1.03

=

8,240

42,000 x 1.03

=

43,260

Vacancy Rate = 8,240 / 51,500 = 16%

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Summary

• Vacancy rate is determined by sampling rate and non-response adjustment.

• There are adjustments for the non-interviews and housing unit controls but they do not impact the vacancy rate.

8

Thank You

If you have any questions or comments:

Edward.C.Castro@census.gov

For more information on the ACS please visit:

http://www.census.gov/acs/www