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USING THE EXPANDED CURF
The nature of the changes made, and the relatively small number of records involved ensure that the effects on data for analysis purposes is considered negligible. The changes mean that estimates produced from the CURF may differ from those published in released publications. Detailed information about the data collected, comments regarding data quality and other points to assist in using and interpreting the data are contained in Australian Health Survey: Users' Guide, 2011-13 (cat. no. 4363.0.55.001). It is recommended that relevant parts of the guide be read in conjunction with the use of the AHS Core Content Expanded CURF. ACCESSING EXPANDED CURFS Expanded CURFs can only be accessed via the Remote Access Data Laboratory (RADL). Users must have applied for use of the RADL prior to using the Expanded CURF microdata. Details on the RADL can be found here - Remote Access Data Laboratory. COUNTING UNITS AND WEIGHTS NUMBER OF RECORDS BY LEVEL, AHS CORE CONTENT 2011-12 EXPANDED CURF
Weights and Hierarchical Files There are 3 weights associated with these files: Household Weight PAA (AHSFHHWT) - Household level - Benchmarked to produce household estimates Person Weight PAA (AHSPERWT) - Selected Person level - Benchmarked to produce population estimates for persons 2 years and over Biomedical Weight PAA (NHMSPERW) - Biomedical level - Benchmarked to produce population estimates for person 5 years and over. Note that this level also contains non-biomedical participant records however their biomedical weight is set to 0 so they won't contribute to estimates. When using biomedical variables inconjunction with other variables on the biomedical level or with variables from other levels, the biomedical weight should be used. There is no weight associated with the Persons in household level. This level is available in order to produce compositional information about the household (e.g. Number of persons in household aged 4-14 years) which can then either be used with the household weight to represent for example the the number of households with at least two persons aged 4-14 years, or with the person weight to represent the number of people living in household that contain at least two persons aged 4-14 years. There is also no weight associated with the Conditions level. This is because the condition records are repeated for each person. If, for example, AHSPERWT is merged onto the conditions level, it will be attached to each condition record and therefore be repeated for each person where they have more than one condition. This should be considered when producing tables. See Copying information across levels below for more information. Using Weights The AHS is a sample survey. To produce estimates for the in-scope population you must use weight fields in your calculations.
Note that when applying the household weight to other levels, the weight will be multiplied by the number of people in the household on that level. If household estimates are desired, then the characteristic variables should be turned into a household variable. As mentioned previously, the desired population output for the conditions level should also be considered prior to applying the person weight. For more information about weights see Reliability of Estimates below. IDENTIFIERS Every record on each level of the file is uniquely identified. The identifiers ABSHHRID, ABSAPRID, ABSSPRID, ABSCNRID, ABSBIRID appear on all levels of the file. Where the information for the identifier is not relevant for a level, it has a value of 0. Relevant identifiers for each level is as follows: 1. Household = ABSHHRID 2. Persons in household = ABSHHRID ABSAPRID 3. Person = ABSHHRID ABSAPRID ABSSPRID 4. Conditions = ABSHHRID ABSAPRID ABSSPRID ABSCNRID 5. Biomedical = ABSHHRID ABSAPRID ABSSPRID ABSBIRID Each household has a unique thirteen digit random identifier, ABSHHRID. This identifier appears on the household level and is repeated on each level on each record pertaining to that household. The combination of identifiers uniquely identifies a record at a particular level. The combination of ABSHHRID ABSAPRID ABSSPRID ABSCNRID identifies each individual condition record a person has. When merging data with a level above, only those identifiers relevant to the level above are required. However, when merging for example the conditions level with the person level, the data on the person level will duplicate for each condition. See Copying information across levels below for more information. COPYING INFORMATION ACROSS LEVELS The following SAS code is an example of copying information from a lower level to a level above: PROC SORT DATA=AHS11ECN; BY ABSHHRID ABSAPRID ABSSPRID; DATA TTLLT (KEEP=ABSHHRID ABSAPRID ABSSPRID LONGTERM CURRNOT); SET AHS11ECN; BY ABSHHRID ABSAPRID ABSSPRID; RETAIN LONGTERM NOTCURR; IF FIRST.ABSSPRID THEN DO; LONGTERM=0; CURRNOT=0; END; /* Note as the file is sorted by the three IDs, reference to first is only needed for the last part of the ID */ IF AHSSTAT=1 THEN LONGTERM=LONGTERM+1; /*starts a count of the number of diagnosed long term conditions*/ IF AHSSTAT=3 THEN CURRNOT=CURRNUT+1; /*starts a count of the number of diagnosed conditions that are not current*/ IF LAST.ABSSPRID THEN OUTPUT; PROC SORT DATA=AHS11ESP; BY ABSHHRID ABSAPRID ABSSPRID; DATA MRGFILES; MERGE TTLLT AHS11ESP; BY ABSHHRID ABSAPRID ABSSPRID; PROC FREQ DATA=MRGFILES; /*This procedure gives a weighted count of the data copied up from the condition level*/ TABLES LONGTERM CURRNOT; WEIGHT AHSPERWT; RUN; The new variables LONGTERM and CURRNOT produce the number of collected conditions a person has that are either diagnosed/longterm or diagnosed/not current. So they are meaningful on the person level, where only one value per record is produced for each variable. Merging the new variables onto the person level allows them to be analysed with any other items on the person level and for weighted estimates to be correctly produced. The following SAS code is an example of copying information from a higher level to a level below: DATA PERSON (KEEP=ABSHHRID ABSAPRID ABSSPRID AGEC SEX); SET AHS11ESP; PROC SORT DATA=PERSON; BY ABSHHRID ABSAPRID ABSSPRID; PROC SORT DATA=AHS11ECN; BY ABSHHRID ABSAPRID ABSSPRID; DATA MRGFILES MERGE AHS11ECN PERSON; BY ABSHHRID ABSAPRID ABSSPRID; RUN; This merge matches one person record to many conditions records. So, the data items copied from the person level ('AGEC' and 'SEX' in the example) will be repeated for the counting unit of the level they have been added to, conditions in this case. RELIABILITY OF ESTIMATES As the survey was conducted on a sample of private households in Australia, it is important to take account of the method of sample selection when deriving estimates from the CURF. This is particularly important as a person's chance of selection in the survey varied depending on the state or territory in which the person lived. If these chances of selection are not accounted for, by use of appropriate weights, the results will be biased. For details on the weighting process see Weighting, Benchmarks and Estimation procedures in Australian Health Survey: Users' Guide, 2011-13 (cat. no. 4363.0.55.001). Each person record has a main weight (AHSPERWT). This weight indicates how many population units are represented by the sample units. When producing estimates of sub-populations from the CURF, it is essential that they are calculated by adding the weights of persons in each category and not just by counting the sample number in each category. If each person's weight were to be ignored when analysing the data to draw inferences about the population, then no account would be taken of a person's chance of selection or of different response rates across population groups, with the result that the estimates produced could be biased. The application of weights ensures that estimates will conform to an independently estimated distribution of the population by age, by sex, etc. rather than to the distributions within the sample itself. Each person record on the CURF contains 60 replicate weights in addition to the main weight. Replicate weights can be used to calculate measures of sampling error. For details on sampling error calculations and replicate weights see the Technical Note in the Australian Health Survey: Users' Guide, 2011-13 (cat. no. 4363.0.55.001). EXPANDED CURF FILES SAS files These files contain the data for the CURF in SAS format. AHS11EHH.sas7bdat contains the Household level data AHS11EAP.sas7bdat contains the Persons in Household level data AHS11ESP.sas7bdat contains the Person level data AHS11ECN.sas7bdat contains the Condition level data AHS11EBI.sas7bdat contains the Biomedical level data SPSS files These files contain the data for the CURF in SPSS format. AHS11EHH.sav contains the Household level data AHS11EAP.sav contains the Persons in Household level data AHS11ESP.sav contains the Person level data AHS11ECN.sav contains the Condition level data AHS11EBI.sav contains the Biomedical level data STATA files These files contain the data for the CURF in STATA format. AHS11EHH.dta contains the Household level data AHS11EAP.dta contains the Persons in Household level data AHS11ESP.dta contains the Person level data AHS11ECN.dta contains the Condition level data AHS11EBI.dta contains the Biomedical level data Information files FORMATS.sas7bcat is a SAS library containing formats Frequency files The following plain text format files contain data item code values and category labels at each level, with weighted and unweighted frequencies for each value. ECURF AHS11E Household freqs.txt contains frequencies for Household level items ECURF AHS11E Persons in Household freqs.txt contains frequencies for Persons in Household level items ECURF AHS11E Person freqs.txt contains frequencies for Person level items ECURF AHS11E Condition freqs.txt contains frequencies for Condition level items ECURF AHS11E Weighted Biomedical freqs.txt contains the weighted frequencies for the Biomedical level items ECURF AHS11E Unweighted Biomedical freqs.txt contains the unweighted frequencies for the Biomedical level items Document Selection These documents will be presented in a new window.
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