ARCHIVE DOCUMENTATION

STUDY NO: 4224 

STUDY TITLE: ONS Omnibus Survey, May 1999

Please note:

Omnibus is intended as a fast turn-around survey and cannot be
edited and cleaned to the same extent as other SSD datasets.	

DETAILS OF DEPOSIT:

Data:

F990501		SPSS Version 9
F9905210	SPSS Version 9
F9905225	SPSS Version 9
F9905228	SPSS Version 9
F9905230	SPSS Version 9

Machine Readable Documentation:

Paper Documentation:

Omnibus Monthly Instructions/interview schedules for the following modules
have been received by the UK Data Archive:
	
M01  Classification Questions
M212 Ethnic Participation in Sport - Data not Deposited with the Archive.
M228 Reading
M225 Cancer Screening
M230 Time Use Diary
M210 Consumption of Tobacco
M207 SHL standardisation - Data not deposited with the Archive.

Showcards

NEW EDITION INFORMATION:

VALIDATION & CONVERSION:

Number of cases/frequencies/documentation checked etc.

Please note that variables 'area' and 'sacorn' have been removed from
the relevant data files at the request of the Depositor, Office for
National Statistics, for confidentiality purposes.

CONVERSION PROCESS:

SUMMARY OF VALUE-ADDED OUTPUTS: 

Frequency, list and descriptive files produced for archiving purposes.
Paper documentation scanned, pdf'd and bookmarked via Adobe Acrobat 3.0

For variable 'Looked', label (3) 'Waiting to take up new job or business 
already obtained' added.

The text for variable 'PaidJob' should read:
'May I just check how many members of your household have a paid job?'

FILE NAME CHANGES:

File 'F9905230.POR' was redeposited as 'C0095230 + diary.sav'.  This file was
then re-named F9905230 by the Archive.

TECHNICAL REPORT RECOMMENDED/ESSENTIAL:

NOTES, USEFUL TIPS AND HINTS:

Weighting Variables: 

WTA, WTC etc. are the weight variables that should be applied to the
data - they do not have variable labels. 

Weighting factors are applied to Omnibus data to correct for unequal
probability of selection caused by interviewing only one adult per
household, or restricting the eligibility of the module to certain types
of informant. It should be noted that this weighting corrects for
unequal probabilities of selection; it does not attempt to correct for
any non-response bias. 

Using weighted data within the calculation of the weight the base is
scaled back to the unweighted total. If a module of questions applied
only to a sub-group of the population, for example eligibility was
restricted by age, or the module was asked only in England, the weight
for the module is calculated for that sub-group and the base, for the
weighted data, scaled back to the unweighted figure. 

When conducting statistical significance tests, using weighted data, the
unweighted base should be used. For tests on the total (module)
population the base shown should be used - because this is the
unweighted base. However, if sub-groups of the total (module) population
are created, for example sub-groups in terms of sex, age-group, region,
etc., the base shown is the weighted base for that sub- group - because
the weight was generated for the whole (module) population. Therefore,
when conducting statistical significance tests on these sub-groups, the
unweighted base for the sub-group should be used - this can be found by
running tables, etc., without applying the weight - in conjunction with
the weighted data. 

i. Unit of analysis: Household. On occasions, a module may collect
information about the household rather than the individual and the
appropriate unit of analysis will be the household rather than the
individual. For example, the questions might be concerned with details
about the accommodation which could be supplied by any adult member of
the household. In this case, no waiting is required because the
information is collected from every household in the responding sample. 

ii	Weight A - Unit of analysis: Individual. Because only one
household member is interviewed, people in households containing few
adults have a better chance of selection than those in households with
many. Weight A is applied to correct for this unequal probability, and
is calculated by dividing the number of adults in the sampled household
by the average number of adults per household. The base is then adjusted
back to the number of informants who were interviewed. Weight A is
applied to modules which use the individual adult as the unit of
analysis. 

iii	Weight C - Unit of analysis: Head of household or spouse
Sometimes information about the household is required that can only be
supplied reliably by the head of household or their spouse/partner. The
probability that the selected informant will be eligible for the module
will be 2/n or 1/n (where n is the number of adults in the household:0
if the head of household is married/cohabiting the probability that the
selected informant will be eligible is 2/n, if the head of household is
not married/cohabiting the probability is 1/n. The weighting factor
corrects for unequal probability of selection and then adjusts the base
back to that of the actual number of informants who complete the module.

USER COMMENTS AND POST-ORDER CORRECTIONS: