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Selection Criteria
The fact sheets do not provide a definitive list of statistics related to literacy. The following criteria were used in deciding what to include in the fact sheets:
- The statistics are from nationally representative samples of the population. State level studies are not included.
- Priority is given to the most recent data available.
- The statistics are quoted from the original source.
- The statistics are easily accessible and readable. Information on survey methodology, the standard deviation, and variance of survey data, for example, is not included.
Common Limitations of the Data
The facts have been obtained from different types of studies. These include:
- telephone surveys, such as the National Household Education Survey (NHES);
- academic research studies, such as the literacy promotion studies
- number counts, for example, the 2000 Census;
- longitudinal studies, such as the Early Childhood Longitudinal Study (ECLS); and
- assessments, such as the National Assessment of Educational Progress (NAEP).
Study design is important to the value and use of research findings. Some things to consider when using facts and statistics are described below with illustrations from the studies included in the NIFL Literacy Fact Sheets.
Responses to surveys are limited by the survey instrument.
- The National Household Education Survey is conducted in English or Spanish. The National Center for Education Statistics acknowledges that the National Household Education Survey on the participation of adults in second language classes underrepresents participation in ESL classes among adults who do not speak either English or Spanish.
Other surveys may be limited by the sample population.
- The National Association of Manufacturers 2001 surveyed only its members on issues relating to employees' skills in the workforce; therefore, the results are not representative of all industries.
The sample size of studies varies considerably, and some sample sizes are too small to produce reliable findings.
- One of the largest studies is the National Adult Literacy Assessment (NALS), which surveyed over 26,000 adults. One of the smallest studies is The Conference Board's study on the economic benefits of workplace education programs, which was based on 100 interviews.
Some statistics are self-reported facts and should be treated with some caution.
- The National Center for Education Statistics acknowledges that in the National Household Education Survey on families' engagement in home literacy initiatives, parents may overestimate both their involvement in home literacy activities and their children's skills because they recognize that such activities and skills are socially desirable.
Many of the studies only provide a description or observations of what is happening and, as such, they do not provide research-based recommendations.
- The Early Childhood Longitudinal Study found that the average mean reading scores of kindergartners were 22 in the Fall and 32 in the following Spring. This tells us that the scores increased over this period, but this does not tell us about expected improvements in mean reading scores of kindergartners over this time frame.
Some statistics go beyond descriptions to indicate that there is a correlation between two factors; however, a correlation between two variables does not mean that one is the cause of another.
- The National Assessment of Educational Progress found a relationship between reading levels and the number of hours spent watching television. Students who watched six or more hours of television a day had, on average, lower reading scores than students who watched zero to two hours a day. This cannot be interpreted to mean that the actual cause of lower reading scores is the television.
Many of the surveys and assessments are conducted on an annual or periodic basis and are designed to compare changes over time. Statistics originating from different studies, however, cannot be compared with each other.
- The National Assessment of Educational Progress long-term trend assessments have the objective of measuring students' performance over time and have remained substantially the same since their first administration. Unlike the long-term assessment, the National Assessment of Educational Progress national assessment is periodically updated to reflect current educational goals. These changes in the actual assessment reduce our ability to measure student changes in performance over the long term.
How to Use the Data
If you are interested in a particular study and would like to find more information, check to see whether the statistics are from one of the main studies in the digest pages. These pages hold more statistics from the following studies:
If you would like more information on the study or want to check publications for previous years, follow the link to the website of the sponsoring organization. A link is provided on each digest page.
The references provide full bibliographic information and, where possible, an html link directly to the document online. (Most of the documents cited are available as PDF files.) For comparative studies conducted in previous years, check the publishers' websites for more information.
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