updated Supporting statement B

B. Statistical Methods

1. Universe and Respondent Selection

The Census of State and Local Law Enforcement Agencies is a web, mail, and fax survey that was first conducted in 1992. Previous iterations of the CSLLEA have collected data on agency functions and number of personnel. Those data will again be a priority, but the need for more specific information related to the recruitment, hiring, and retention of sworn officers has necessitated developing additional questions to be included for a sample of agencies. These data will help identify successful recruitment, hiring, and retention practices, which can be used by agencies experiencing staff shortages.

The Governments Division (GOVS) of the Census Bureau was responsible for CSLLEA data collection in 1992, 1996, and 2000. In an effort to achieve cost savings in the interests of both the Federal government and the U.S. taxpayer, BJS began outsourcing data collection with the 2004 CSLLEA. A private data collection contractor was selected through a competitive solicitation process. This process will used for the 2008 CSLLEA as well. For aspects of the project related to the CJ-38L (long) form, BJS has retained responsibility for the sample design and imputation phases.

The 2-page CJ-38S form to be used in the 2008 CSLLEA will be based on the 2004 CSLLEA, and will be sent to 15,775 agencies. The 4-page CJ-38L form will consist of the same content as the CJ-38S form plus two additional pages of questions related to recruitment, hiring, and retention of sworn personnel. The long form will be sent to a nationally representative sample of 3,225 agencies, including a certainty sample of the 997 large law enforcement agencies (those with 100 or more officers), and a stratified random sample of 2,228 smaller agencies (strata based on agency size and type).

The sample design is based on a design developed by the Economic and Statistical Methods and Programming Division (ESMPD) of the Census Bureau for the LEMAS survey. This design was used most recently for the 2007 LEMAS survey. BJS will continue the practice of including all agencies with 100 or more sworn personnel so that an existing longitudinal study of such agencies may be continued. Below that level, the stratified sample design developed by ESMPD will be used.  This is a statistically valid design in accordance with currently accepted standards based on the expertise of those involved at ESMPD.  Using the same sample as the 2007 LEMAS survey will allow for the inclusion of data from that survey that are relevant to the issues of recruitment, hiring and retention during the analyses of the data collected in the 2008 CSLLEA

 

a. Universe

The universe for the 2008 CSLLEA will consist of all State and local law enforcement agencies operating in the U.S. as of September 30, 2008, that are publicly funded and employ at least one full-time or part-time sworn officer with general arrest powers. Types of agencies to be included are sheriffs= offices, municipal general purpose police, county general purpose police, state police/highway patrol, tribal police, special jurisdiction police, and constable offices.

b. Sample of agencies receiving 4-page (CJ-38L) form

The agencies selected to receive the 4-page (CJ-38L) form will be separated into two groups for the purpose of sample selection: self-representing (SR) and non-self-representing (NSR) agencies. All state police are SR. The definitions of SR and NSR are shown below.

1. Self-representing agencies

An agency is SR if it meets one of the following two criteria:

1. An agency is a State Police agency

2. An agency has 100 or more sworn full-time equivalent (FTE) employees.

Number of sworn FTE = rounded [(# sworn full time employees) + 0.5 * (# sworn part-time employees)]

2. Non-self-representing agencies

All remaining sheriffs’ offices and local police departments are NSR.

Below is the complete sample design information for 2008:

Type of agency	Total agencies	Short- Form	Sampled agencies (long form)			NSR Universe	Weight
			Total	SR	NSR
State law enforcement	49	0	49	49	0	--	--
Sheriffs offices	3,067	2,067	1,000	351	649	2,716	4.18
Local police - total	13,684	11,508	2,176	597	1579		--
Stratum 1	--	--	224	--	224	479	2.14
Stratum 2	--	--	224	--	224	757	3.38
Stratum 3	--	--	259	--	259	1,282	4.95
Stratum 4	--	--	248	--	248	1,758	7.09
Stratum 5	--	--	306	--	306	2,953	9.65
Stratum 6	--	--	319	--	319	4,945	15.55
Special jurisdiction	1,700	1,700	0	0	0	--	--
Texas constables	500	500	0	0	0	--	--
Totals	19,000	15,775	3,225	997	2,228	--	--

 

                

c. Out-of-scopes

Although uncommon, an agency can be out-of-scope for the 2008 CSLLEA because it disbanded since the 2004 CSLLEA. This problem is minimized because BJS obtains a current listing of all law enforcement agencies from the Police Officer Standards and Training agency in each State, and also obtains a list of agencies receiving new ORI Agency Identifiers from the FBI since the 2004 CSLLEA.

d. Creating cells for weighting and imputation

Cells for weighting and imputation within SR/NSR agency types will be created by crossing average number of sworn officers with size of population served for Local Police agencies and State Police agencies. For Sheriff=s Departments, average number of full-time equivalents will be crossed with employee categories (number of employees working in jails, courts, and law enforcement), and whether or not the department had a jail. Collapsed type of agency, average number of sworn officers, average number of full-time equivalents, subtype for special agencies, and size of population served come from the universe file.

Cells will be required to have at least 15 respondents and an agency response rate of at least 70%. Cells will be collapsed within SR/NSR status and collapsed type of agency if either of those criteria were not met.

e. Weighting the sample receiving the CJ-38L (long) form

The base weight for all SR agencies will be one. For NSR agencies, the stratum and associated base weights will be determined by the number of sworn personnel employed as reported in the 2004 census. The final weight associated with every agency, both SR and NSR, is the product of the base weight and a factor that adjusts for non-responding agencies in each cell.

2. Procedures for Collecting Information

The survey will be conducted initially by mail-out, with a web-based response option. The address mailing list will be updated prior to mail-out in order to maintain a current list of the respondents. Personal telephone interviews will be conducted for non-respondents.

3. Methods to Maximize Response

We will do everything possible to maximize response, including telephone facsimile transmission, E-mail transmission, telephone interviews, and on-site assistance. The response rate for the 2004 CSLLEA exceeded 99%. It is expected that at least a 99% response rate will be obtained for the 2-page CJ-38S form being used for the 2008 CSLLEA. At least a 99% response rate will be obtained for the core CJ-38S portion of the 4-page CJ-38L form and at least 90% for the supplemental 2-page section on recruitment, hiring, and retention.

4. Testing of Procedures

The survey instrument will be pre-tested in selected jurisdictions by individuals that will be receiving the survey instrument. The pretest will involve State, regional, county, and local agencies. Any comments received as a result of that testing will be incorporated into the survey instrument before data collection begins.

5. Contacts for Statistical Aspects and Data Collection

Person to contact for information on statistical methodology, conducting the survey, and analyzing the data:

Brian A. Reaves, Ph.D.

Law Enforcement Unit

Bureau of Justice Statistics

810 Seventh St., NW

Washington, DC 20531

(202) 616-3287

C. Attachments

1. Copy of the survey forms

2. Copy of the regulatory authority (42 U.S.C. 3732)