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NAEP Instruments → Contextual Items (Survey Questionnaires) → Indices Based on Questionnaire Data → Development of the 2018 Grade 8 U.S. History Indices

NAEP Technical DocumentationDevelopment of the 2018 Grade 8 U.S. History Indices

For the 2018 grade 8 U.S. history assessment, several indices of policy interest were developed that satisfied both theoretical criteria based on content analysis, and empirical criteria based on multivariate statistical techniques. This resulted in the creation of several new reporting elements. The development of the 2018 grade 8 U.S. history indices can be summarized in three main steps:

1. Question development. New sets of contextual items, such as those exploring students’ persistence in learning and their enjoyment of complex problems, were developed and included in the U.S. history student questionnaire. Through content analysis as part of the item development process, only sets of items that were theoretically interpretable and meaningful as a conceptual unit were included as potential indices to measure specific constructs of interest.

2. Examination of empirical relationships. Factor analysis was used to explore and verify the empirical properties of the data. Construct validity of the potential indices was evaluated through factorial validity with respect to the survey question responses, and the convergent and discriminant validity of the factor with respect to other factors. If the factor had the expected pattern of relationships and non-relationships, the construct validity of the factor as representing the intended index was supported.

3. Index scoring. The partial credit item response theory (IRT) model was used to scale the indices. Scaling of the index items was first conducted to get the item parameters and was based on marginal maximum likelihood methodologies. After the parameters were estimated, expected a posteriori (EAP) scores were calculated as the estimate of the index score. Then, the EAP scores were transformed to have a mean of 10 and a standard deviation of 2 on a scale from 0–20.

Index of Students' Persistence in Learning

The table below presents the items forming the index of students' persistence in learning. This index was designed to measure students' tendency to persevere and work hard in the face of challenges. Grade 8 students were asked to indicate how much each of the four statement items described a person like them (not at all like me, a little bit like me, somewhat like me, quite a bit like me, or very much like me).

Items in the index of eighth-grade students' persistence in learning, grade 8 U.S. history national assessment: 2018
How much does each of the following statements describe a person like you? Select one answer choice on each row.
Response categories
Item			Not at all like me	A little bit like me	Somewhat like me	Quite a bit like me	Very much like me
B034901	a.	I finish whatever I begin.	A	B	C	D	E
B034902	b.	I try very hard even after making mistakes.	A	B	C	D	E
B034903	c.	I keep working hard even when I feel like quitting.	A	B	C	D	E
B034904	d.	I keep trying to improve myself, even when it takes a long time to get there.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students' Academic Self-Discipline

The table below presents the items forming the index of students' academic self-discipline. This index was designed to measure students' tendency to pay attention and stay on task when learning. Grade 8 students were asked to indicate how often they have done each of the four statement items (never or hardly ever, less than half of the time, about half of the time, more than half of the time, or all or almost all of the time).

Items in the index of eighth-grade students' academic self-discipline, grade 8 U.S. history national assessment: 2018
In this school year, how often have you done each of the following? Select one answer choice on each row.
Response categories
Item			Never or hardly ever	Less than half of the time	About half of the time	More than half of the time	All or almost all of the time
B035001	a.	I started working on assignments right away rather than waiting until the last minute.	A	B	C	D	E
B035002	b.	I paid attention and resisted distractions.	A	B	C	D	E
B035003	c.	I stayed on task without reminders from my teacher.	A	B	C	D	E
B035004	d.	I paid attention in class even when I was not interested.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students' Enjoyment of Complex Problems

The table below presents the items forming the index of students' enjoyment of complex problems. This index was designed to measure students' enjoyment of problems and activities that challenge them to think. Grade 8 students were asked to indicate how much each of the four statement items described a person like them (not at all like me, a little bit like me, somewhat like me, quite a bit like me, or very much like me).

Items in the index of eighth-grade students' enjoyment of complex problems, grade 8 U.S. history national assessment: 2018
How much does each of the following statements describe a person like you? Select one answer choice on each row.
Response categories
Item			Not at all like me	A little bit like me	Somewhat like me	Quite a bit like me	Very much like me
B035101	a.	I like complex problems more than easy problems.	A	B	C	D	E
B035102	b.	I like activities that challenge my thinking abilities.	A	B	C	D	E
B035103	c.	I enjoy situations where I will have to think about something.	A	B	C	D	E
B035104	d.	I enjoy thinking about new solutions to problems.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students’ Interest/Enjoyment in U.S. History

The table below presents the items forming the index of students' interest/enjoyment in U.S. history. This index was designed to measure students' interest in and enjoyment of U.S. history topics, and their views of the importance of learning about U.S. history. Grade 8 students were asked to indicate how much each of the five statement items described them (not at all like me, a little bit like me, somewhat like me, quite a bit like me, or exactly like me).

Items in the index of eighth-grade students' interest/enjoyment in U.S. history, grade 8 U.S. history national assessment: 2018
How much does each of the following statements describe you? Select one answer choice on each row.
Response categories
Item			Not at all like me	A little bit like me	Somewhat like me	Quite a bit like me	Exactly like me
H813701	a.	United States history is one of my favorite subjects to study.	A	B	C	D	E
H813702	b.	I enjoy doing schoolwork about United States history.	A	B	C	D	E
H813703	c.	I enjoy discussing United States history topics with others.	A	B	C	D	E
H813704	d.	I think that United States history schoolwork helps me understand what is happening in the world around me.	A	B	C	D	E
H813705	e.	I think that learning about United States history topics will be important for my future.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students’ Confidence in U.S. History Knowledge and Skills

The table below presents the items forming the index of students' confidence in their U.S. history knowledge and skills. This index was designed to measure students' belief in their abilities to do various U.S. history-related tasks. Grade 8 students were asked to indicate their confidence in doing the task described in each of seven items (I definitely can’t, I probably can’t, maybe, I probably can, or I definitely can).

Items in the index of eighth-grade students' confidence in U.S. history knowledge and skills, grade 8 U.S. history national assessment: 2018
Do you think that you would be able to do each of the following? Select one answer choice on each row.
Response categories
Item			I definitely can't	I probably can't	Maybe	I probably can	I definitely can
H813401	a.	Explain the causes and effects of important events in United States history	A	B	C	D	E
H813402	b.	Explain how time periods in United States history are similar or different	A	B	C	D	E
H813403	c.	Judge whether information from a source (for example, text, visual graphics, video, or audio) is accurate	A	B	C	D	E
H813404	d.	Understand the relationship between two historical events	A	B	C	D	E
H813405	e.	Compare and evaluate different points of view about the past (for example, different ideas about what caused the Civil War)	A	B	C	D	E
H813406	f.	Come up with research questions about why or how something happened in the past (for example, what were the causes of the Great Depression)	A	B	C	D	E
H813407	g.	Take and defend a position about a historical issue (for example, how changes in transportation have affected the United States economy)	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students’ Performance Goals in U.S. History

The table below presents the items forming the index of students' performance goals in U.S. history. This index was designed to measure students' motivation to show that they are a good student and get better U.S. history grades than others in their class. Grade 8 students were asked to indicate how much each of the four statement items described them (not at all like me, a little bit like me, somewhat like me, quite a bit like me, or exactly like me).

Items in the index of eighth-grade students' performance goals in U.S. history, grade 8 U.S. history national assessment: 2018
How much does each of the following statements describe you? Select one answer choice on each row.
Response categories
Item			Not at all like me	A little bit like me	Somewhat like me	Quite a bit like me	Exactly like me
H813501	a.	I want other students to think I am a good United States history student.	A	B	C	D	E
H813502	b.	I want to show others that my United States history schoolwork is easy for me.	A	B	C	D	E
H813503	c.	I want to look smart in comparison to the other students in my social studies or United States history class.	A	B	C	D	E
H813504	d.	I want to get better United States history grades than most other students in my class.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students’ Mastery Goals in U.S. History

The table below presents the items forming the index of students' mastery goals in U.S. history. This index was designed to measure students' motivation to learn as much as they can about U.S. history and master new skills in their class. Grade 8 students were asked to indicate how much each of the four statement items described them (not at all like me, a little bit like me, somewhat like me, quite a bit like me, or exactly like me).

Items in the index of eighth-grade students' mastery goals in U.S. history, grade 8 U.S. history national assessment: 2018
How much does each of the following statements describe you? Select one answer choice on each row.
Response categories
Item			Not at all like me	A little bit like me	Somewhat like me	Quite a bit like me	Exactly like me
H813601	a.	I want to learn as much as possible about United States history in my class.	A	B	C	D	E
H813602	b.	I want to master a lot of new United States history skills in my class.	A	B	C	D	E
H813603	c.	I want to become a better United States history student this year.	A	B	C	D	E
H813604	d.	I want to understand as much as I can about United States history in my class.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index of Students’ Perspective Taking in Historical Thinking

The table below presents the items forming the index of students' perspective taking in their historical thinking. This index was designed to measure students' tendency to consider different perspectives when thinking about historical events. Grade 8 students were asked to indicate how much each of the five statement items described them (not at all like me, a little bit like me, somewhat like me, quite a bit like me, or exactly like me).

Items in the index of eighth-grade students' perspective taking in historical thinking, grade 8 U.S. history national assessment: 2018
How much does each of the following statements describe you? Select one answer choice on each row.
Response categories
Item			Not at all like me	A little bit like me	Somewhat like me	Quite a bit like me	Exactly like me
H813301	a.	I form opinions about historical events only after I have information from more than one source.	A	B	C	D	E
H813302	b.	I need to know the history leading up to an event to truly understand it.	A	B	C	D	E
H813303	c.	I want to know what lies behind the story when I study a conflict in history.	A	B	C	D	E
H813304	d.	I try to understand others better by imagining how things look from their perspective.	A	B	C	D	E
H813306	f.	I think that there is more than one side to every question, and I try to look at all of them.	A	B	C	D	E
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Index Item Scoring

Analyses were conducted separately for the paper-based assessment (PBA) and digitally based assessment (DBA) samples. While most 2018 grade 8 U.S. history indices are reported based on DBA data, one index (students' persistence in learning) is reported based on the combined PBA and DBA data because the missing rates for the items within this index were ≤15% in the PBA and DBA modes. PBA and DBA tables are provided for this index in the sections that follow.

For each index item, the response categories were scored as numerical values (e.g., for an item with five response categories, category A was scored as 1, B was scored as 2, C was scored as 3, D was scored as 4, and E was scored as 5). For the one 2018 grade 8 U.S. history PBA index and three of the 2018 grade 8 U.S. history DBA indices, item response categories were collapsed; scores for a five-category item thus became 1, 2, 3, and 4 after collapsing. The tables below describe the treatment of the index items.

Recoding of polytomous items for scaling, grade 8 U.S. history PBA national assessment, by index: 2018
Item	Index	Reason for decision	Disposition
B034901	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B034902	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B034903	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B034904	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
NOTE: Only indices with missing rates less than or equal to 15 percent are reported. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Recoding of polytomous items for scaling, grade 8 U.S. history DBA national assessment, by index: 2018
Item	Index	Reason for decision	Disposition
B034901	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B034902	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B034903	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B034904	Persistence in learning	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035001	Academic self-discipline	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035002	Academic self-discipline	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035003	Academic self-discipline	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035004	Academic self-discipline	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035101	Enjoyment of complex problems	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035102	Enjoyment of complex problems	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035103	Enjoyment of complex problems	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
B035104	Enjoyment of complex problems	To improve model-data fit	Collapse categories: 1,2,3,4,5 becomes 1,1,2,3,4
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT Parameters

The partial credit IRT model was used to scale the indices. Scaling of the index items was first conducted to get the item parameters and was based on marginal maximum likelihood methodologies. The following tables show the IRT parameters for the 2018 grade 8 U.S. history indices.

IRT parameters for items in the index of eighth-grade students' persistence in learning, grade 8 U.S. history PBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
B034901	-0.31	0.97	0.07	-1.04	†	†
B034902	-0.57	0.74	0.07	-0.81	†	†
B034903	-0.40	0.68	0.08	-0.76	†	†
B034904	-0.83	0.61	0.06	-0.66	†	†
† Not applicable. NOTE: PBA = Paper-based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' persistence in learning, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
B034901	-0.29	0.98	0.05	-1.03	†	†
B034902	-0.51	0.76	0.05	-0.81	†	†
B034903	-0.33	0.71	-0.01	-0.70	†	†
B034904	-0.75	0.60	0.02	-0.62	†	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' academic self-discipline, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
B035001	0.08	0.75	-0.05	-0.70	†	†
B035002	-0.09	0.89	0.07	-0.96	†	†
B035003	-0.37	0.68	0.06	-0.74	†	†
B035004	-0.20	0.70	0.02	-0.72	†	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' enjoyment of complex problems, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
B035101	0.56	0.76	-0.04	-0.72	†	†
B035102	0.03	0.77	-0.03	-0.74	†	†
B035103	0.07	0.78	-0.03	-0.75	†	†
B035104	-0.02	0.68	-0.03	-0.64	†	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' interest/enjoyment in U.S. history, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
H813701	0.27	0.65	0.44	-0.39	-0.69	†
H813702	0.39	0.89	0.53	-0.39	-1.03	†
H813703	0.18	0.78	0.49	-0.42	-0.85	†
H813704	-0.04	0.96	0.51	-0.42	-1.05	†
H813705	-0.03	0.83	0.43	-0.44	-0.82	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' confidence in U.S. history knowledge and skills, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
H813401	-0.26	1.33	0.85	-0.50	-1.68	†
H813402	-0.38	1.48	0.73	-0.51	-1.70	†
H813403	-0.38	1.36	0.73	-0.51	-1.58	†
H813404	-0.58	1.38	0.83	-0.48	-1.73	†
H813405	-0.47	1.32	0.76	-0.48	-1.60	†
H813406	-0.48	1.26	0.68	-0.48	-1.46	†
H813407	-0.51	1.19	0.66	-0.52	-1.33	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' performance goals in U.S. history, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
H813501	-0.06	0.84	0.55	-0.39	-0.99	†
H813502	0.17	0.81	0.58	-0.43	-0.96	†
H813503	0.00	0.70	0.48	-0.42	-0.76	†
H813504	-0.40	0.84	0.41	-0.39	-0.86	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' mastery goals in U.S. history, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
H813601	-0.34	1.18	0.59	-0.54	-1.24	†
H813602	-0.20	1.22	0.58	-0.52	-1.28	†
H813603	-0.55	1.17	0.50	-0.45	-1.21	†
H813604	-0.60	1.10	0.52	-0.50	-1.12	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

IRT parameters for items in the index of eighth-grade students' perspective taking in historical thinking, grade 8 U.S. history DBA national assessment: 2018
Item	b_j	d_j1	d_j2	d_j3	d_j4	d_j5
H813301	0.10	0.99	0.56	-0.42	-1.13	†
H813302	-0.21	1.05	0.54	-0.43	-1.16	†
H813303	-0.23	0.92	0.47	-0.41	-0.98	†
H813304	-0.26	1.03	0.50	-0.41	-1.11	†
H813306	-0.33	0.99	0.44	-0.47	-0.96	†
† Not applicable. NOTE: DBA = Digitally based assessment. The number of dji parameters is one less than the number of categories for the item. For items scaled with the partial credit model, parameters a and c are not estimated. The a parameter value is exactly one and the c parameter is exactly zero. For item j, bj represents a location parameter related to item difficulty, and dji represents the category threshold parameter for category i of item j; dji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response Averages and Transformed Scores

After the parameters were estimated, EAP scores were calculated as the estimate of the index score, and transformed to a reporting scale of 0–20. The tables below show the response averages and transformed scale scores for each of the grade 8 U.S. history indices. Note that response averages represent the average scored responses after score collapsing (if there was any collapsing). Each response average corresponds to one transformed score. The increment used for increases in the response average is determined by the number of items that form an index. For example, an index with four items would have response averages that increase by an increment of 1 / 4 or 0.25, while an index with five items would have response averages that increase by an increment of 1 / 5 or 0.20.

As a reporting aid, index scores were divided into a range of categories or classifications (e.g., low, moderate, high). The cut points selected to divide the index scores into meaningful categories were based on the distributions of the response average of each index.

As an example, for the index of persistence in learning, grade 8 students were classified as follows:

Students with a response average less than 2 were classified as low on the index. That is, students who on average responded closest to not at all like me on a question with the five response options not at all like me, a little bit like me, somewhat like me, quite a bit like me, and very much like me were classified as having a low level of persistence in learning.
Students with a response average greater than or equal to 2 to less than 3 were classified as having a moderate level of persistence in learning.
Finally, students with a response average greater than or equal to 3 were classified as high on the index. That is, students who on average responded closest to very much like me were classified as having a high level of persistence in learning.

Response averages and transformed scores for the index of eighth-grade students' persistence in learning, grade 8 U.S. history PBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	5.8	2
	1.25	6.6	3
	1.50	7.2	3
	1.75	7.7	4
Moderate	2.00	8.2	6
	2.25	8.6	6
	2.50	9.0	8
	2.75	9.5	9
High	3.00	9.9	12
	3.25	10.4	12
	3.50	11.0	13
	3.75	11.8	12
	4.00	12.8	11
NOTE: PBA = Paper-based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' persistence in learning, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	5.9	3
	1.25	6.7	3
	1.50	7.4	3
	1.75	7.9	5
Moderate	2.00	8.3	6
	2.25	8.7	5
	2.50	9.1	9
	2.75	9.6	9
High	3.00	10.0	13
	3.25	10.5	11
	3.50	11.1	11
	3.75	11.8	11
	4.00	12.9	12
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' academic self-discipline, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	6.4	4
	1.25	7.3	3
	1.50	7.9	5
	1.75	8.4	7
Moderate	2.00	8.9	9
	2.25	9.3	8
	2.50	9.7	11
	2.75	10.1	10
High	3.00	10.6	11
	3.25	11.1	10
	3.50	11.6	8
	3.75	12.3	6
	4.00	13.2	6
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' enjoyment of complex problems, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	6.8	12
	1.25	7.7	7
	1.50	8.4	7
	1.75	9.0	9
Moderate	2.00	9.4	11
	2.25	9.9	7
	2.50	10.3	8
	2.75	10.7	7
High	3.00	11.1	8
	3.25	11.6	6
	3.50	12.1	5
	3.75	12.7	5
	4.00	13.6	8
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' interest/enjoyment in U.S. history, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	6.4	8
	1.20	7.2	3
	1.40	7.8	4
	1.60	8.2	4
	1.80	8.6	5
	2.00	8.9	6
	2.20	9.2	4
	2.40	9.5	5
	2.60	9.7	5
	2.80	10.0	5
Moderate	3.00	10.3	12
	3.20	10.5	5
	3.40	10.8	5
	3.60	11.1	5
	3.80	11.4	4
High	4.00	11.7	5
	4.20	12.0	3
	4.40	12.4	2
	4.60	12.8	3
	4.80	13.3	2
	5.00	14.1	5
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' confidence in U.S. history knowledge and skills, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	4.5	2
	1.14	5.2	#
	1.29	5.6	#
	1.43	6.0	#
	1.57	6.3	#
	1.71	6.6	1
	1.86	6.9	1
	2.00	7.2	2
	2.14	7.4	1
	2.29	7.7	2
	2.43	8.0	2
	2.57	8.2	3
	2.71	8.5	3
	2.86	8.8	4
Moderate	3.00	9.0	13
	3.14	9.3	5
	3.29	9.6	6
	3.43	9.9	6
	3.57	10.2	6
	3.71	10.5	6
	3.86	10.8	6
High	4.00	11.2	8
	4.14	11.5	4
	4.29	11.8	3
	4.43	12.2	3
	4.57	12.6	2
	4.71	13.1	2
	4.86	13.7	2
	5.00	14.4	4
# Rounds to zero. NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' performance goals in U.S. history, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	6.3	6
	1.25	7.1	3
	1.50	7.6	4
	1.75	8.1	4
	2.00	8.5	7
	2.25	8.8	5
	2.50	9.2	7
	2.75	9.5	6
Moderate	3.00	9.8	11
	3.25	10.2	6
	3.50	10.5	6
	3.75	10.8	6
High	4.00	11.2	8
	4.25	11.6	4
	4.50	12.1	4
	4.75	12.8	3
	5.00	13.6	9
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' mastery goals in U.S. history, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	5.4	5
	1.25	6.1	1
	1.50	6.7	2
	1.75	7.2	2
	2.00	7.6	6
	2.25	8.0	3
	2.50	8.4	5
	2.75	8.8	5
Moderate	3.00	9.2	13
	3.25	9.6	5
	3.50	10.0	7
	3.75	10.5	6
High	4.00	10.9	11
	4.25	11.4	4
	4.50	11.9	5
	4.75	12.6	5
	5.00	13.5	14
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Response averages and transformed scores for the index of eighth-grade students' perspective taking in historical thinking, grade 8 U.S. history DBA national assessment, by classification: 2018
Classification	Response average	Transformed score	Percentage of students
Low	1.00	5.7	4
	1.20	6.5	1
	1.40	7.0	2
	1.60	7.4	2
	1.80	7.8	3
	2.00	8.1	4
	2.20	8.5	4
	2.40	8.8	5
	2.60	9.0	6
	2.80	9.3	6
Moderate	3.00	9.6	12
	3.20	9.9	7
	3.40	10.2	7
	3.60	10.5	7
	3.80	10.8	7
High	4.00	11.2	7
	4.20	11.5	5
	4.40	11.9	4
	4.60	12.4	3
	4.80	13.0	3
	5.00	13.8	4
NOTE: DBA = Digitally based assessment. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 U.S. History Assessment.

Last updated 31 March 2025 (SK)

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​​​​​​​​​​NAEP Technical DocumentationDevelopment of the 2018 Grade 8 U.S. History Indices

NAEP Technical DocumentationDevelopment of the 2018 Grade 8 U.S. History Indices