Conference on Data Quality
for International Organisations
(Rome, Italy, 7-8 July 2008)
Session 1: Assessment of data quality
The example of the Wages part in the
ILO Yearbook of Labour Statistics
(http://laborsta.ilo.org)
Le Anh Hua (hua@ilo.org)
Bureau of Statistics
International Labour Office
Geneva, Switzerland
Overview of the presentation
•
•
•
•
The ILO tools for ensuring quality
Some statistics in Laborsta
Data collection instruments
What we do to check the quality of the
statistics reported
• Forms of dissemination
• Measurements linked to the statistics
• Points of concern for discussion
ILO tools for ensuring quality
• Set of procedures to ensure
consistency, timeliness and coherence
– Standardised questionnaires pre-filled with earlier
statistics, and with instructions and classifications
– Methodological descriptions
– Correspondence and follow up with countries
• Database documentation
Wage statistics in Laborsta
(last observation in 2004 or later)
Table 5A
by economic
activity
91 countries 142
time
series
4000 time
lines
Table 5B
91 countries 135
time
manufacturing
series
4600 time
lines
Data collection instruments
• Questionnaires, incl. instructions and annexes
with classifications
• On the following slides
–
–
–
–
–
1st page with contact information
Overview of concepts, units, coverage, source
Table 5A, by ISIC tabulation categories
Table 5B, by divisions of manufacturing
Table 5C, for agricultural activities
ST-125-63 / Part 5
Country: AAA
INTERNATIONAL LABOUR OFFICE
QUESTIONNAIRE FOR
THE YEARBOOK OF LABOUR STATISTICS,
2008
WAGES
Data provided by your country will be entered in the
Bureau of Statistics' principal database, LABORSTA,
and made available on its Website
(http://laborsta.ilo.org).
In order to be included in the
2008 edition of the Yearbook of Labour Statistics
and in the corresponding CD-ROM ,
data must reach the ILO by 30 June 2008.
>> Instructions
>> 5A - Average wages per hour and per person, by economic activity
>> 5B - Average wages per hour and per person, in manufacturing, and by division
>> 5C - Average wages per hour per person in agricultural activities, by sex
Agency/organization responsible for the statistics:
Person who may be contacted for further information about the statistics
- Name:
- Address:
- Fax number:
- Tel. number:
- E-mail address:
- Web site:
ST-125-63 (5A) AAA - series I
Table 5.A - ISIC-Rev.3 - Average wages per hour and per person, by economic activity
Country: AAA
Currency: AAA
CONCEPT, TIME UNIT AND PERSONS COVERED:
Concept:
- Average earnings
- Average wage rates
- Other (specify)
Time unit:
- Per hour (a)
- Per day
- Per week
- Per month
(a) Please, specify:
- Per hour actually worked
- Per hour paid for
- Per normal hour
Persons covered:
- All employees (wage earners and
salaried employees)
- Wage earners
- Salaried employees
- All persons employed
- Other (specify)
If the coverage is "wage earners" or "salaried employees", please provide the operational
definition used in your country to identify them in practice
SOURCE OF DATA:
- Establishment survey
- Administrative records
- Labour force survey
- Other
TITLE:
REFERENCE PERIOD:
PUBLICATION(S)/WEBSITE(S) IN WHICH
DATA APPEAR:
TOTAL (MEN+WOMEN)
Economic activity
ISIC-Rev.3
Average, all activities (A-Q)
Average, non-agricultural activities
(C-Q)
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
X
1998 1999 2000
.
.
.
.
25.44
26.78
30.05
24.83
.
.
.
.
.
.
.
.
.
.
.
.
.
26.04
27.53
30.71
25.22
.
.
.
.
.
.
.
.
.
.
.
.
.
26.31
27.78
30.83
25.02
.
.
.
.
.
.
.
.
.
.
.
.
Notes: (1) 2001: change in the currency - conversion factor
2001
2002 2003 2004 2005 2006
.
.
.
.
13.96
14.72
16.50
13.39
.
.
.
.
.
.
.
.
.
.
.
.
(1)
13.66
14.42 (1)
16.13 (1)
(1)
13.06
.
.
.
.
.
.
.
.
.
.
.
.
.
.
2007
.
.
.
.
.
.
14.29 14.6 14.76
15.09 15.4 15.60
17.07 17.61 18.16
13.71 13.87 13.90
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
14.81
15.74
18.55
13.79
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
ST-125-63 (5B)
- series I
Table 5.B - ISIC Rev. 3 - D - Average wages per hour and per person, in
in manufacturing, and by division
TOTAL (MEN+WOMEN)
Manufacturing
ISIC Rev. 3 - D
Average, divisions (15-37)
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
1998
.
22.68
27.70
20.57
18.36
18.96
23.27
25.29
29.55
32.09
28.04
23.62
23.80
28.14
24.96
28.01
25.98
25.79
25.25
25.33
33.92
27.68
23.36
19.88
1999
.
23.30
28.28
20.98
18.90
19.48
23.88
26.07
30.53
32.88
28.55
24.16
24.31
28.83
25.49
28.77
26.05
26.51
26.08
25.98
35.21
28.64
23.82
20.18
2000
.
23.27
29.21
20.82
18.88
19.61
23.62
26.75
30.70
33.98
29.37
24.50
24.48
30.05
25.66
29.19
25.18
26.36
26.44
25.80
35.24
29.16
23.82
20.51
Notes: (1) Prior to 2001: DEM; 1 Euro = 1.95583 DEM.
2001
.
12.11(1)
14.08(1)
10.84(1)
9.83(1)
10.05(1)
12.21(1)
13.88(1)
15.95(1)
17.86(1)
15.22(1)
12.69(1)
12.71(1)
15.55(1)
13.28(1)
15.14(1)
13.12(1)
13.65(1)
13.66(1)
13.31(1)
18.08(1)
15.31(1)
12.40(1)
10.85(1)
2002
.
12.38
15.70
11.11
10.09
10.28
12.42
14.18
16.19
18.14
15.54
13.06
12.96
15.93
13.60
15.49
13.49
14.06
13.92
13.59
18.01
15.76
12.67
11.28
2003
.
12.70
16.05
11.25
10.25
10.50
12.56
14.53
16.39
19.00
15.85
13.34
13.29
16.23
13.86
15.92
13.59
14.41
14.24
13.95
18.58
16.13
12.91
11.38
2004
.
12.94
16.53
11.56
10.45
10.57
12.74
14.84
16.49
19.40
15.93
13.52
13.44
16.63
14.05
16.32
13.41
14.73
14.37
14.27
19.24
16.33
13.07
11.67
2005
.
13.12
16.24
11.59
10.55
10.60
12.75
15.00
16.56
19.35
16.13
13.69
13.51
16.85
14.21
16.55
13.40
14.91
14.46
14.50
19.56
16.67
13.18
11.77
2006
.
13.27
16.03
11.69
10.86
10.71
12.78
15.28
16.41
19.82
16.24
13.80
13.66
17.23
14.37
16.73
13.45
15.07
14.55
14.62
19.59
16.91
13.26
11.94
2007
.
Assessment criteria
•
•
•
•
•
Official statistics?
Source, coverage, time unit, currency units
Divergence from main concepts
Upward/downward variation from trend
New series v. old series
• National websites & national publications
• Metadata available facilitate quality control
checks
Variation from trends
• Are the newly submitted values reasonable?
– Change in currency ?
– CPI ?
– Typing mistake in the reported figures ?
• Data identified as possible error
– corrected from original or supplementary
information
– Enquiry with data supplier for correction
– If unresolved: not disseminated.
Old series v. new series
Possible situations
• Old series not updated, but new series
provided
• Old series updated, and new series
provided
• Existing series not updated
• Tables returned empty
Validation tests
• consistency across tables: average for D
(manufacturing) in 5A should be identical to “total”
in 5B
• consistency within tables: average for total (♀+♂) ≤
maximum ♀ & ♂ , and ≥ minimum ♀ & ♂
• implausible values: average for Total (♀+ ♂) ≠
arithmetic mean (♀+♂) (except in the case of an
identical wage rate for men and women)
• If break in series then note shown at the year
• Coherence between source of series and source in
“Sources & Methods”
Forms of dissemination
• http://laborsta.ilo.org
– Statistical series and methodological information
– Display on screen and downloadable files
• ILO Yearbook of Labour statistics
• Sources & methods publications
– Volume 2: Establishment Surveys: Employment, Wages,
Hours of Work and Labour Cost
– Volume 4: Administrative Records and Related
Sources: Employment, Unemployment, Wages and
Hours of Work
Measurements linked to the
statistics
•
•
•
•
•
•
•
No. of hits on Laborsta
No. of requests by email/telephone.
No. of series updated each year
No. of responses processed each year
User satisfaction survey on the web
Problems observed and resolved
Running review of lessons learned and
ways to make the processes more efficient
Points of concern for discussion
• How to « fill the gaps » in the available series ?
• What could be done to improve the response rates ?
• Should we also consider using non-official statistics ?
• What are the main quality concerns for an international
gathering and dissemination of statistics from countries ?
– Country coverage (geographical, persons) ?
– Time series length and coherence?
– Comparability between countries ?
• Can the quality of the series be quantitatively expressed ?