Definition Adult literacy rate is defined as the percentage of population aged 15 years and over who can both read and write with understanding a short simple statement on his/her everyday life. Adult illiteracy is defined as the percentage of the population aged 15 years and over who cannot both read and write with understanding a short simple statement on his/her everyday life.
Purpose Adult literacy rate shows the accumulated achievement of primary education and literacy programmes in imparting basic literacy skills to the population, thereby enabling them to apply such skills in daily life and to continue learning and communicating using the written word. Literacy represents a potential for further intellectual growth and contribution to economic-socio-cultural development of society. Illiteracy rates indicate the extent of need for policies and efforts in organizing adult literacy programmes and quality primary education.
Calculation method Divide the number of literates by the corresponding age-group population and multiply the result by 100. Alternatively, apply the same method using the number of illiterates to derive the illiteracy rate ; or by subtracting literacy rate from 100%.
Formula:
or
Where:
= Adult Literacy
Rate (15+) in year t
= Adult
Illiteracy Rate (15+) in year t
= Adult Literate
Population (15+) in year t
= Adult Illiterate Population
(15+) in year t
= Adult Population
(15+) in year t
+ 
=
100%
Data required Population and number of literates (or illiterates) aged 15 years and over.
Data source Mainly National population census ; household and/or labour force surveys.
Types of disaggregation This indicator should be calculated by gender, geographical location (region, urban/rural) and by the following five-year age-groups: 1519; 2014; 2519; 30-34; 35-39; 40-44; 45-49; 50-54; 55-59; 60-64; 65 and above.
Interpretation High literacy rate (or low illiteracy rate) indicates a wide coverage of the primary education system and/or literacy programmes in that a large proportion of the population have acquired the ability of using the written word in daily life and to continue learning. It is common practice to present and analyse literacy rates together with the absolute number of adult illiterates as improvements in literacy rates may sometimes be accompanied by increases in the illiterate population due to the changing demographic structure.
Quality standards It will be useful to align measurements of literacy with the standard international definition given above, and to administer literacy tests on a sample basis to verify and improve the quality of literacy statistics.
Limitations It has been observed that some countries apply definitions and criteria for literacy which are different from the international standards defined above, or equate persons with no schooling to illiterates, or change definitions between censuses. Practices for identifying literates and illiterates during actual census enumeration may also vary, as well as errors in literacy self-declaration can affect the reliability of literacy statistics.