Early Learning and Child Well-being in the United States

Reader’s guide

What is IELS?

The International Early Learning and Child Well-being Study (IELS) puts a spotlight on how children are faring at five years of age. IELS directly measures key indicators of children’s learning, as well as collecting a broad range of development and contextual information from children’s parents and teachers.

What aspects of learning and development were of focus in IELS?

IELS conceptualises early learning as holistic, involving cognitive and socio-emotional skills whose development are interrelated and mutually reinforcing. The study does not measure everything. Instead, it focuses on those aspects of development and learning that are predictive of children’s later education outcomes and wider well-being. These are: emergent literacy and emergent numeracy, self-regulation, and social-emotional skills. Across these main early learning domains, 10 dimensions of children’s development and learning were assessed in the study.

Who participated in IELS?

Three OECD countries participated in the study: England, Estonia and the United States. This report uses “England” as shorthand for England (United Kingdom). IELS covered children who were aged between five and six years of age during the study administration period of October to December 2018 and who were enrolled in a registered school or early childhood education centre. Samples were drawn and weighted to be representative of the target populations in each of the three participating countries. This report uses “five-year-olds” as shorthand for the IELS target population.

Educators and parents also participated in IELS by providing contextual information about children’s learning and lives. “Educators” is the term used to describe the teachers or early childhood education and care (ECEC) staff members who responded to staff questionnaires in IELS. The report uses “parents” as shorthand for the parents, guardians or others who completed the IELS parent questionnaire with respect to participating children.

What does this volume contain?

The results from IELS are presented in four reports: an international report and an in-depth report on each of the three participating countries. This volume focuses on the findings for the United States.

A guide to interpreting findings in this report

Data underlying the report

IELS results are based on direct and indirect assessment of children’s skills in a range of learning domains. The metric for all learning scales in IELS is the same and the metric used for the scales does not have a substantive meaning (unlike physical units of measure, such as ounces or yards). There is theoretically no minimum or maximum score in IELS; rather, the data are scaled to have approximately normal distributions, with the means around 500 and standard deviations (see below) around 100. A one-point difference on the IELS scale therefore corresponds to an effect size of .01 of a standard deviation and a 10-point difference to an effect size of .1. Results are presented for a subgroup of children only when estimates are based on at least 30 children from at least five ECEC centres or schools. Important contextual information about children’s lives and learning was collected from their parents and educators. Some information was collected only from educators, some only from parents, and in some cases, parents and educators both provided perspectives on the same issue (e.g. how well a child is developing in a particular domain). When parent and educator reports are compared in tables, figures or text in this report, those analyses are based on the subsample of children for whom both parents and educators provided information.

Overall IELS averages

Where cross-country averages are provided in any of the IELS volumes, these averages correspond to the arithmetic mean of the three country estimates.

Statistically significant differences

Unless otherwise stated, a difference reported as statistically significant is significant at the .05 level. This means there is a less than 5% probability that the reported difference occurred by chance; a statistical test has been carried out to establish this. Statistically significant differences in this report are denoted by darker tones in figures and by bold font in tables.

Interpreting correlations

A correlation coefficient is a measure of the degree to which two variables tend to move together. The coefficient has a value between plus and minus 1, which indicates the strength and direction of association. If a correlation is positive, it means that as one variable increases, so does the other. If a correlation is negative, it means that as one variable increases, the other decreases. In this report, a correlation coefficient with an absolute value between 0 and 0.19 is interpreted as weak, between 0.20 and 0.49 as moderate, between .50 and 0.79 as strong, and between 0.80 and .99 as very strong.

Standard deviation

The standard deviation is a measure of the dispersion of a set of data from its mean. The more spread apart the data, the higher the deviation. In a normal distribution, 68% of the scores are within one standard deviation of the mean, 95% within two standard deviations, and 99% within three. As mentioned above, IELS learning scales all have an approximate standard deviation of 100.

Standard Error

Scores reported in this volume are population estimates, based on the sample of children selected. However, it is unlikely that the ‘true’ or population mean is exactly the same as the sample. Some variation or error around estimates is to be expected. Thus, each mean has a standard error, which allows us to estimate how accurately the mean found in our sample reflects the ‘true’ mean in the population. The ‘true’ mean score can be found in an interval that is 1.96 standard errors on either side of the obtained mean, 95% of the time.

Rounding figures

As a result of rounding, some figures in tables may not add up exactly to the totals. Totals, averages and differences are calculated on the basis of exact numbers and are rounded only after calculation. Percentages and mean scores are rounded to whole numbers, and standard errors are rounded to two decimal places.

Additional technical information

Readers interested in additional technical detail regarding IELS are directed towards the short technical note at the end of this volume and to the IELS Technical Report (OECD, forthcoming).

This report uses the OECD StatLinks service, meaning that all tables and figures are assigned a URL leading to an Excel workbook containing the underlying data. These URLs are stable and will remain unchanged over time. In addition, readers of the e-books will be able to click directly on these links, and the workbook will open in a separate window if their Internet browser is open and running.