Glossary: Constructs and Variables Used in the Analyses

A list of definitions and sources for the variables used in this report is presented below (in order of appearance). Several of the variables were derived by combining information from one or more questions in the ECLS-B parent interview or from other study sources. The names of the source variables as presented on the ECLS-B longitudinal data file are shown within brackets and in all capital letters after the variable description. More information on the derivation of key variables in the ECLS-B longitudinal data file is included in chapter 7 of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), Preschool Data File User's Manual (2005–06) (Snow et al. 2007).

• Child's sex [X3CHSEX]. Information for this composite is taken from the birth certificate. However, child's sex was confirmed in the parent interview. If the parent interview indicated a different sex than the birth certificate, the parent interview information was considered to be most accurate.
• Child's race/ethnicity [X3CHRACE]. At the 9-month parent interview, respondents indicated whether the child belonged to one or more of 14 race categories: (1) White, (2) Black or African American, (3) American Indian or Alaska Native (AIAN), (4) Asian Indian, (5) Chinese, (6) Filipino, (7) Japanese, (8) Korean, (9) Vietnamese, (10) Other Asian, (11) Native Hawaiian, (12) Guamanian or Chamorro, (13) Samoan, and (14) Other Pacific Islander. Data were collected on Hispanic ethnicity as well; specifically, respondents were asked whether the child was of Hispanic or Latino origin. During the 2-year parent interview, for cases that were identified as being of AIAN descent in the 9-month collection (by either the birth certificate data or during the parent interview), parent interview respondents were asked to confirm the child was of AIAN descent. If the parent interview respondent indicated "no," the case was reclassified as the race/ethnicity specified by the parent interview respondent. Similar procedures were repeated at the preschool round. In this First Look report, the categories for race/ethnicity are as follows: White, non-Hispanic; Black or African American, non-Hispanic; Hispanic; Asian, non-Hispanic; American Indian or Alaska Native, non-Hispanic; and Other, non-Hispanic (Native Hawaiian/other Pacific Islanders and children of more than one race). A child's ethnicity was classified as Hispanic if a parent respondent indicated the child's ethnicity was Hispanic, regardless of the race identified.
• Plurality [X1MBRTST]. Plurality was based on information on children's birth certificates. The birth certificate data indicated whether a child was a singleton, twin, or higher order (e.g., triplet, quadruplet, quintuplet, or higher).
• Birth weight [X1BTHWGT]. Birth weight was based on children's weight at the time of their birth as collected on the birth certificate. This particular measure categorized birth weight as: normal (more than 5.5 pounds); moderately low (more than 3.3 to 5.5 pounds); and very low (3.3 pounds or less).
• Child's age at the time of assessment [X3ASAGE]. The composite variable X3ASAGE was calculated as follows: If the respondent to the parent interview agreed with the child's date of birth as shown on the birth record, then the child's age was calculated by determining the number of days between the date when the child completed the ECLS-B direct child assessment and the date of birth indicated on the birth record. If the child's date of birth on the birth record was determined to be incorrect by the parent respondent, then the child's age was calculated by determining the number of days between the date when the child completed the direct child assessment and the date of birth reported in the parent interview. The total number of days was then divided by 30 to calculate child's age in months. The date of the direct child assessment came from the following sources in order of priority: (1) the assessment date noted in the Child Activity Booklet; (2) the assessment date on the front cover of the Child Activity Booklet; and (3) the date of the parent interview. If the child assessment was completed during more than one home visit, the child's age was calculated as the average of the age calculated from the first home visit and the age calculated from the last home visit of the preschool data collection. The preschool data collection of the ECLS-B was intended to assess children in the fall of 2005, when the majority of the sample would be about 48 through 57 months of age. However, children were assessed when they were as young as 44 months and as old as 65 months. Tables 3 through 6 present estimates only for those children within the target range of the assessment (48 through 57 months of age).
• Family type [X3HPARNT]. Information collected in the household roster matrix of the parent interview was used to construct the household composition variable X3HPARNT. For this First Look report, the original categories for X3HPARNT were collapsed as follows:
  • two parent (includes biological mother and biological father OR biological mother and other father [step-, adoptive, foster] OR biological father and other mother [step-, adoptive, foster] OR two adoptive parents OR adoptive parent and stepparent);
  • single parent (includes biological mother only OR biological father only OR single adoptive parent); and
  • other parent type (includes related guardian(s) OR unrelated guardian(s)).
• Mother's employment status [X3HMEMP]. This variable is computed for the person identified as the mother or mother figure in the household (birth mother, adoptive mother, stepmother, foster mother, or mother figure as specified by the respondent to the parent interview). In the parent interview, information about mother's employment status was collected through a series of questions about whether or not the mother worked for pay, how many hours per week she worked, and, if she was not working, whether she was looking for work or not in the labor force (not working by choice). This First Look report presents information on mother's employment status, at the time of the preschool parent interview, using the following categories: full time, 35 hours or more per week; part time, less than 35 hours per week; looking for work; not in the labor force; or no mother in the household.
• Socioeconomic status [X3SESQ5]. Socioeconomic status (SES) is a measure of social standing. This SES variable reflects the socioeconomic status of the household at the time of the preschool parent interview, in 2005. The components used to create the measure of SES were as follows: father/male guardian's education; mother/female guardian's education; father/male guardian's occupation; mother/female guardian's occupation; and household income. For technical information on how SES was derived, please see chapter 7 of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), Preschool Data File User's Manual (2005–06) (Snow et al. 2007). In this report, SES was collapsed first into quintiles, then into a 20 percent/60 percent/20 percent distribution by collapsing the middle three quintiles.
• Children's language knowledge and skills [X3RECVOC; X3EXPLNG]. For language, the receptive vocabulary score was calculated using Item Response Theory (IRT) procedures. To reduce burden, children were administered an adaptive test; all children did not receive the same range of items. The IRT-based scores represent estimates of the number of items children would have answered correctly had they been administered all items. Therefore, the IRT scale scores estimate children's performance on the whole set of items included in the score. The scores are not integers; they consist of probabilities of correct answers, summed over all items in the score. For more information on the IRT modeling, please refer to the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), Methodology Report for the Preschool Data Collection (2005–06), Volume I: Psychometrics (Najarian, Lennon, and Snow 2007).
  • Children's receptive vocabulary knowledge and skills [X3RECVOC]. Broadly defined, receptive vocabulary involves a child's ability to demonstrate he/she understands the meaning of words (for instance, asking a child to point to a picture that represents a word spoken by the interviewer). The receptive vocabulary score has a possible range of 0 to 15. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the receptive vocabulary score ranges from 5 to 14 with a standard deviation of 2.
  • Children's expressive language [X3EXPLNG]. The telling stories subscale for the language domain was adapted from the PreLAS 2000 (DeAvila 1998). For the ECLS-B preschool assessment, two short stories were read to each child. After each story, the child was asked to retell the story, making reference to a set of pictures provided as prompts. The field interviewers tape-recorded the child's response. Specially trained coders at RTI subsequently scored these responses following the holistic scoring instructions provided for the items. Using the following system, scores have a possible range of 0-5, where 0 = no response, including "I don't know"; 1 = short, isolated phrases, with at least one word in English; 2 = disconnected thoughts, with at least one sentence, many grammar errors; 3 = recognizable story line, limited detail, grammar errors; 4 = a recognizable version of a story in coherent, fluent sentences, and 5 = articulate, detailed sentence, vivid vocabulary, and complex constructions. The composite variable is a mathematical average of the individual scores on the two stories. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the expressive language score ranges from 0 to 5 with a standard deviation of 1.
• Children's literacy knowledge and skills [X3LITSC; X3PHONO; X3PRINT; X3LTR]. For literacy, the overall scale score and the phonological awareness, conventions of print, and letter recognition scores were calculated using IRT procedures. To reduce burden, children were administered an adaptive test; all children did not receive the same range of items. The IRT-based scores represent estimates of the number of items children would have answered correctly had they been administered all items. Therefore, the IRT scale scores estimate children's performance on the whole set of items included in the score. The scores are not integers; they consist of probabilities of correct answers, summed over all items in the score. The assessments were designed to scale with the kindergarten assessment so that the ECLS-B could potentially offer a common metric for children's preschool and kindergarten literacy knowledge and skills. Therefore, the average score of preschool-aged children may seem low relative to the range of the scale (leaving room to measure developing literacy skills across the year in time for the entering kindergarten assessment). For more information on the IRT modeling please refer to the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), Methodology Report for the Preschool Data Collection (2005–06), Volume I: Psychometrics (Najarian, Lennon, and Snow 2007).
• Children's overall literacy knowledge and skills [X3LITSC]. Children's overall literacy knowledge and skills include letter recognition, in both receptive and expressive modes; letter sounds; and early reading (e.g., recognition of simple words, phonological awareness, and knowledge of print conventions). The overall literacy knowledge and skills score has a possible range of 0 to 37. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the overall literacy score ranges from 5 to 35 with a standard deviation of 7.
• Children's phonological awareness knowledge and skills [X3PHONO]. Phonological awareness is the understanding of the sounds and structure of spoken language, including rhyming, blending, segmenting, deleting, and substituting words, syllables, and sounds. The phonological awareness score has a possible range of 0 to 8. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the phonological awareness score ranges from 2 to 7 with a standard deviation of 1.
• Children's conventions of print knowledge and skills [X3PRINT]. Conventions of print refers to the understanding of what print represents and how it works (e.g., print reads left to right, top to bottom). The conventions of print score has a possible range of 0 to 8. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the conventions of print score ranges from 1 to 7 with standard deviation 1.
• Children's letter recognition knowledge and skills [X3LTR]. Letter recognition refers to the ability to identify a letter either by its name or the sound it makes. Unlike the other scores (which reflect specific literacy knowledge and skills that are scaled on a metric reflecting the number of items in the specific content strand) the letter recognition score has a possible range of 0 to 1, expressed as a probability that a child would get the cluster of items correct. For the purpose of this report, these scores are expressed as a percentage (probability score multiplied by 100) and, for example, can be interpreted as the percentage of children who were proficient at recognizing the letters of the alphabet. This score has a possible range of 0 to 100. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the letter recognition score ranges from 2 to 99 with a standard deviation of 26.
• Children's mathematics knowledge and skills [X3MTHSC; X3NMBR]. For mathematics, both the overall scale score and the number recognition score were calculated using IRT procedures. To reduce burden, children were administered an adaptive test; all children did not receive the same range of items. The IRT-based scores represent estimates of the number of items children would have answered correctly had they been administered all items. Therefore, the IRT scale scores estimate children's performance on the whole set of items included in the score. The scores are not integers; they consist of probabilities of correct answers, summed over all items in the score. For more information on the IRT modeling please refer to the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), Methodology Report for the Preschool Data Collection (2005–06), Volume I: Psychometrics (Najarian, Lennon, and Snow 2007).
• Children's overall mathematics knowledge and skills [X3MTHSC]. Children's overall mathematics knowledge and skills include number sense, geometry, counting, operations, and patterns. The overall mathematics knowledge and skills score has a possible range of 0 to 44. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the overall mathematics score ranges from 6 to 42 with a standard deviation of 7.
• Children's number and shape recognition knowledge and skills [X3NMBR]. Number and shape recognition refers to children's ability to recognize single-digit numbers and basic geometric shapes. Unlike some of the other scores (which reflect specific knowledge and skills that are scaled on a metric reflecting the number of items in the specific content strand), the number and shape recognition score (similar to the letter recognition score) has a possible range of 0 to 1, expressed as a probability that a child would get the cluster of items correct. For the purpose of this report, these scores are expressed as a percentage (probability score multiplied by 100) and, for example, can be interpreted as the percentage of children who were proficient at recognizing single-digit numbers and basic geometric shapes. This score has a possible range of 0 to 100. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the numbers and shapes score ranges from 0 to 100 with a standard deviation of 39.
• Children's color knowledge [X3COLOR]. The color knowledge scale score is a number right score that ranges from 0 to 10 and reflects children's ability to recognize basic colors. The color knowledge test asked children to name the colors of 5 teddy bears (out of 10 pictured), with each correct answer receiving 2 points. For all of the colors that the child could not initially name, the assessor asked, "Can you find the [blue] bear?" Children received 1 point per correct answer in this receptive mode. For this report, the score was collapsed into three categories: none (a score of 0); some (a score of 1 to 9); and all (a score of 10, meaning the child was able to identify all 5 colors without being prompted to point to a specific color). The color knowledge and skills score has a possible range of 0 to 10. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the color knowledge score ranges from 0 to 10 with a standard deviation of 2.
• Children's fine motor skills [X3FMFORM]. This report provides information on children's fine motor skill in drawing basic forms and shapes. The child was provided with seven forms to copy: a vertical line, a horizontal line, a circle, a square, a cross, a triangle, and an asterisk. These copy form items were scored as pass/fail. This score has a possible range of 0 to 7. This First Look report largely presents estimates for children 48 through 57 months of age at the time of assessment. For children 48 through 57 months of age at the time of assessment, the fine motor skills score ranges from 0 to 7 with a standard deviation of 2.
• Child's primary type of nonparental early care and education [X3PRIMNW]. Parents were asked if they currently had regular early care and education arrangements for their child, and, if so, were then asked how many hours per week their child spent in that setting. This composite measure presents information on the type of nonparental care and education in which the child spent the most hours, which is identified as the primary care arrangement. The composite was created by reviewing the number of hours the child spent in each arrangement, and identifying the one where the child spent the most hours. If a child spent equal time in each of two or more types of arrangements, X3PRIMNW is coded as "multiple care arrangements." Children with no regular nonparental care arrangements are coded as "no child care" on X3PRIMNW. For this presentation of primary care, Head Start refers to services received at a public or private school, religious center, or private home, as reported by the parent. "Regular" was defined as arrangements that occurred on a routine schedule (i.e., occurring at least weekly or on some other schedule), not including occasional babysitting or "back-up" arrangements.

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