Multiple Year (2006 ~ 2010) Child Asthma Call-back Survey Prevalence Tables – Technical Information

The Child Asthma Call-back survey (ACBS) requires use of the Behavioral Risk Factor Surveillance System (BRFSS) Random Child Selection Module and Child Asthma Prevalence Module during the BRFSS survey interview. A BRFSS survey respondent is eligible for the child ACBS if they report that the randomly selected child in the household has ever been diagnosed with asthma (lifetime asthma). The number of children with lifetime asthma identified during the BRFSS interview differs depending on the state BRFSS sample size and typically ranges from 200 to 1,000. Due to sample loss between the BRFSS interview and the asthma Call-back interview the number of completed child interviews for the ACBS ranged from 25 to 304 for the years from 2006 through 2010 (Table A). Effective in 2009, the state child data were not weighted and were not included in the annual public release file if there were fewer than 75 interview records for children due to concerns regarding the reliability of the sample weights when so few records were available. Because the ACBS annual sample size for children was limited even in states with a sufficient number to weight, the data for all states implementing the child ACBS from 2006 through 2010 were combined and reweighted. Combining records from all the years each state implemented the child ACBS provides more stable estimates of the characteristics of children with asthma in each state than those resulting from single years. Estimates of the characteristics of the child population with asthma from 35 states and the District of Columbia are included in the multiple-year child tables. Most states contributed four or five years of data to the multiple year file. Table A contains child ACBS sample sizes by year and state.

The annual child ACBS weighting process is based on the BRFSS final child weight for the randomly selected child (_CHILDWT). The sum of the BRFSS child weights for records reporting children with lifetime asthma is an estimate of the total population of children in the state with lifetime asthma. For the ACBS weight, the BRFSS child weight for the randomly selected child is adjusted for loss to sample between the BRFSS interview and the asthma Call-back interview. After adjusting for sample loss, demographic post stratification group (age/sex/race) adjustments are made to account for differential non-response. As an end result of the adjustment for sample loss and the post stratification adjustment, for each state the sum of the ACBS final weights for all ACBS child records is equal to the estimated total state population of children with lifetime asthma in the state.

The reweighting process for the multiple year data file used to produce the child estimates in tables 1 to 14 followed a procedure similar to that used on individual year data files. The multiple years of data were adjusted to represent an average individual year lifetime asthma population for each state. Based on the annual BRFSS child lifetime asthma population estimates, each year’s total estimated child lifetime asthma population was proportionately adjusted to represent that year’s relative contribution to multiple years of combined data. After the proportionate adjustment for the estimated lifetime asthma population, the weights were further adjusted by post-stratifying for differential non-response by demographic subgroups.

Additional information on the ACBS can be accessed at: https://www.cdc.gov/asthma/ACBS.htm and https://www.cdc.gov/brfss/acbs/index.htm.

Table A: Child Asthma Call-back Sample Size by Year and State
State 2006 2007 2008 2009 2010 Sample size
Alabama* *
Alaska* * *
Arizona 51 52 57 * 38 198
Arkansas
California 92 80 73 * 32 277
Colorado
Connecticut 148 119 101 96 85 549
Delaware
District of Columbia 25 44 47 29 36 181
Florida
Georgia 128 149 88 103 77 545
Hawaii 141 188 148 116 104 697
Idaho
Illinois 45 69 77 67 258
Indiana 106 81 86 107 120 500
Iowa 67 86 92 63 66 374
Kansas 165 127 145 279 111 827
Kentucky
Louisiana 88 73 161
Maine 63 115 117 81 61 437
Maryland 142 117 134 134 97 624
Massachusetts 109 60 96 94 60 419
Michigan 89 129 185 131 146 680
Minnesota
Mississippi 112 112
Missouri 97 80 85 65 327
Montana 60 70 54 75 81 340
Nebraska 109 133 178 154 143 717
Nevada
New Hampshire 72 70 90 232
New Jersey 119 190 149 458
New Mexico 93 101 68 93 355
New York 102 100 110 92 39 443
North Carolina
North Dakota 49 54 57 160
Ohio 141 133 45 27 346
Oklahoma 109 100 36 90 335
Oregon 84 81 67 49 50 331
Pennsylvania 92 117 209
Rhode Island 91 78 68 237
South Carolina
South Dakota
Tennessee
Texas 107 127 169 169 208 780
Utah 117 105 168 183 573
Vermont 124 120 122 121 110 597
Virginia 70 72 142
Washington 304 290 594
West Virginia 85 71 71 47 274
Wisconsin 77 63 54 35 44 273
Wyoming
Total 2,158 2,985 3,206 3,179 3,034 14,562

* Child data were collected, but records could not be weighted due to sample issues

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