Reader’s Guide

Data underlying the figures

Detailed data tables corresponding to the figures presented in the main body of the report can be found in Annex A. These figures and tables are numbered according to the corresponding chapters. Tables include an abbreviation in brackets to denote one of the three direct measures of skills for which there are data in the Survey of Adult Skills (PIAAC) – literacy (L), numeracy (N) and problem solving in technology-rich environments (P). As an example, Table A3.1 (L) denotes the first data table based on the literacy scale in Annex A corresponding to figures in Chapter 3 or cited in the main body of the chapter. Unless otherwise stated, the population underlying each of the figures and tables covers adults aged 16-65.

Web package

Figures included in the report and the corresponding data tables contained in Annex A present data for only one of the three direct measures of skills, either literacy (L), numeracy (N) or problem solving in technology-rich environments (P). A more complete set of data can be found at www.oecd.org/site/piaac/. This web package includes all the figures and tables included in the report as well as data tables for the other skills domains referred to but not examined in the report. The package consists of Excel^® workbooks that can be viewed and downloaded by chapter.

StatLinks

A StatLink URL address is provided under each figure and table. Readers using the pdf version of the report can simply click on the relevant StatLinks url to either open or download an Excel^® workbook containing the corresponding figures and tables. Readers of the print version can access the Excel^® workbook by typing the StatLink address in their Internet browser.

Calculating international averages (means)

Most figures and tables presented in this report and in the web package include an OECD average in addition to values for individual countries or sub-national entities. The average in each figure or table corresponds to the arithmetic mean of the respective estimates for each of the OECD countries or sub-national entities included in the figure or table. In the calculation of the OECD average, England (United Kingdom) and Northern Ireland (United Kingdom) are treated as separate entities. The United States contributes to the average of OECD countries as one observation. This is calculated as the mean of the relevant statistic for the two US observations (i.e. in 2012/14 and 2017). Cyprus*, Ecuador, Kazakhstan, Peru, the Russian Federation** and Singapore are not included in the OECD averages presented in any of the figures or tables.

Standard error (S.E.)

The statistical estimates presented in this report are based on samples of adults, rather than values that could be calculated if every person in the target population in every country had answered every question. Therefore, each estimate has a degree of uncertainty associated with sampling and measurement error, which can be expressed as a standard error. The use of confidence intervals provides a way to make inferences about the population means and proportions in a manner that reflects the uncertainty associated with the sample estimates. In this report, confidence intervals are stated at 95% confidence level. In other words, the result for the corresponding population would lie within the confidence interval in 95 out of 100 replications of the measurement on different samples drawn from the same population.

Statistical significance

Differences considered to be statistically significant from either zero or between estimates are based on the 5% level of significance, unless otherwise stated. In the figures, statistically significant estimates are denoted in a darker tone.

Symbols for missing data and abbreviations

a	Data are not applicable because the category does not apply.
c	There are too few observations or no observation to provide reliable estimates (i.e. there are fewer than 30 individuals). Also denotes unstable marginal probabilities which may occur when probabilities are very close to 0 or 1.
m	Data are not available. The data are not submitted by the country or were collected but subsequently removed from the publication for technical reasons.
w	Data have been withdrawn at the request of the country concerned.
S.E.	Standard Error
S.D.	Standard Deviation
Score dif.	Score-point difference between x and y
% dif.	Difference in percentage points between x and y
Marg. Prob.	Marginal probability
(L)	Literacy domain
(N)	Numeracy domain
(P)	Problem solving in technology-rich environments domain
GDP	Gross Domestic Product
ISCED	International Standard Classification of Education
ISCO	International Standard Classification of Occupations

Country coverage

This publication features data on 32 OECD countries (or regions within these countries): Australia, Austria, Canada, Chile, the Czech Republic, Denmark, England (United Kingdom), Estonia, Finland, Flanders (Belgium), France, Germany, Greece***, Hungary, Ireland, Israel, Italy, Japan, Korea, Lithuania, Mexico, the Netherlands, New Zealand, Northern Ireland (United Kingdom), Norway, Poland, the Slovak Republic, Slovenia, Spain, Sweden and the United States. In addition, seven countries that are not members of the OECD participated in the survey: Cyprus*, Ecuador, Jakarta (Indonesia), Kazakhstan, Peru, the Russian Federation** and Singapore.

The United States**** participated in the first and third rounds of the survey. Results for Jakarta (Indonesia) were published in OECD (2016[7]). Data for Jakarta (Indonesia) were subsequently withdrawn from public access and are not presented in this report.

The names of the countries participating in Round 3 of the Survey of Adult Skills are presented in blue in all figures and tables.

Rounding

Data estimates, including mean scores, proportions and standard errors, are generally rounded to one decimal place. Therefore, even if the value (0.0) is shown for standard errors, this does not necessarily imply that the standard error is zero, but that it is smaller than 0.05.

Education levels

The classification of levels of education is based on the International Standard Classification of Education (ISCED 1997). A revised version of ISCED (ISCED 2011) was adopted by the UNESCO General Conference at its 36th session in November 2011 (UIS, 2012[1]). Member States have applied ISCED 2011 in the reporting of their education statistics from 2014. Data on educational participation and attainment from Round 1 of the Survey of Adult Skills were coded using the ISECD 1997 classification. To maintain comparability with the data from Round 1 and Round 2, data from Round 3 have also been coded using ISCED 1997.

Further documentation and resources

The details of the technical standards guiding the design and implementation of the Survey of Adult Skills (PIAAC) can be found at www.oecd.org/site/piaac/. Information regarding the design, methodology and implementation of the Survey of Adult Skills can be found in summary form in The Survey of Adult Skills: Reader’s Companion, Third Edition (OECD, 2019[2]) and, in detail, in the Technical Report of the Survey of Adult Skills, Third Edition (OECD, 2019[3]).

*Note regarding Cyprus

Note by Turkey

The information in this document with reference to “Cyprus” relates to the southern part of the Island. There is no single authority representing both Turkish and Greek Cypriot people on the Island. Turkey recognises the Turkish Republic of Northern Cyprus (TRNC). Until a lasting and equitable solution is found within the context of the United Nations, Turkey shall preserve its position concerning the “Cyprus issue”.

Note by all the European Union Member States of the OECD and the European Union The Republic of Cyprus is recognised by all members of the United Nations with the exception of Turkey. The information in this document relates to the area under the effective control of the Government of the Republic of Cyprus.

Throughout this report, including the main body, boxes and annexes, Cyprus is accompanied by a symbol referring to this note.

**Note regarding the Russian Federation

The sample for the Russian Federation does not include the population of the Moscow municipal area. The data published, therefore, do not represent the entire resident population aged 16-65 in the Russian Federation but rather the population of the Russian Federation excluding the population residing in the Moscow municipal area. More detailed information regarding the data from the Russian Federation as well as that of other countries can be found in the Technical Report of the Survey of Adult Skills, Third Edition (OECD, 2019[3]).

***Note regarding Greece

The data for Greece include a large number of cases (1 032) in which there are responses to the background questionnaire but where responses to the assessment are missing. Proficiency scores have been estimated for these respondents based on their responses to the background questionnaire and the population model used to estimate plausible values for responses missing by design derived from the remaining 3 893 cases. More details can be found in the Technical Report of the Survey of Adult Skills, Third Edition (OECD, 2019[3]).

**** Note regarding the United States

The United States has collected three waves of data using the PIAAC instruments. It collected data as part of Round 1 of Cycle 1 of PIAAC in 2011-12. It then collected additional data for targeted population groups as part of a National PIAAC Supplement (Rampey et al., 2016[4]) in 2014 and participated in Round 3 of Cycle 1. Details of the PIAAC data collection in the United States can be found in the technical reports for the survey and the National PIAAC Supplement (Hogan et al., 2016[5]); (OECD, 2019[3]).

In this report, the results from the United States are reported using the combined data from 2012 and 2014, and the 2017 data collection conducted as part of Round 3.

Results are presented in the charts and tables as separated observations (United States 2012/2014 and United States 2017) but the United States contributes to the OECD average as one observation (taking the mean of the two US observations).

The 2012/14 data set has been used as this is believed to provide a more accurate representation of the proficiency of the working-age population at that point in time than the original 2011-12 data reported in the first two international reports on PIAAC (OECD, 2013[6]; OECD, 2016[7]). In addition to the increased sample size, the 2012/14 data have been weighted to control totals related to the 2010 census whereas the 2011-12 data were weighted to totals related to the census in 2000.

References

[5] Hogan, J. et al. (2016), Main Study and National Supplement Technical Report (NCES 2016-036REV), U.S. Program for the International Assessment of Adult Competencies (PIAAC) 2012/2014, National Center for Education Statistics, Institute of Education Sciences, U.S. Department of Education. Washington, D.C., https://nces.ed.gov/pubs2016/2016036_rev.pdf.

[3] OECD (2019), Technical Report of the Survey of Adult Skills, Third Edition, http://www.oecd.org/skills/piaac/publications/PIAAC_Technical_Report_2019.pdf.

[2] OECD (2019), The Survey of Adult Skills: Reader’s Companion, Third Edition, OECD Skills Studies, OECD Publishing, Paris, https://doi.org/10.1787/f70238c7-en.

[7] OECD (2016), Skills Matter: Further Results from the Survey of Adult Skills, OECD Skills Studies, OECD Publishing, Paris, https://doi.org/10.1787/9789264258051-en.

[6] OECD (2013), OECD Skills Outlook 2013: First Results from the Survey of Adult Skills, OECD Publishing, Paris, https://doi.org/10.1787/9789264204256-en.

[4] Rampey, B. et al. (2016), Skills of US Unemployed, Young, and Older Adults in Sharper Focus: Results from the Program for the International Assessment of Adult Competencies (PIAAC) 2012/2014. First Look. NCES 2016-039, National Center for Education Statistics, Institute of Education Sciences, U.S. Department of Education, Washington, D.C.

[1] UIS (2012), International Standard Classification of Education ISCED 2011, UNESCO Institute for Statistics.

Reader’s Guide