NAEP 2026 Appendix C Sampling Memo

NATIONAL CENTER FOR EDUCATION STATISTICS

NATIONAL ASSESSMENT OF EDUCATIONAL PROGRESS

National Assessment of Educational Progress (NAEP) 2026

Appendix C

2026 Draft Sampling Memo

OMB# 1850-0928 v.36

May 2025

.

NOTE: The final approved 2026 Sampling Memo will be provided in the upcoming 2026 Amendment #1.

Date:	February 28, 2025	Memo: 2026-1.1A/1.1B/1.1D/1.1E/1.1I
	William Ward, NCES
	David Freund, ETS	William Wall
	Laura Jerry, ETS	Marcie Hickman
	Amy Dresher, ETS	Dwight Brock
	Raymond Gross, ETS	Yiting Long
To:	Natalia Andrews, ETS	Sabrina Zhang
	Yue Jia, ETS	Amy Lin
	Pat Stearns, Pearson	Sarah Shore
	Lauren Byrne	Jing Kang
	Lisa Rodriguez
	Chris de los Santos
From:	Véronique Lieber
Reviewers:	Lloyd Hicks, Leslie Wallace, Jay Clark, Tom Krenzke, Keith Rust
Subject:	Sample Design for 2026 NAEP – DRAFT

1. Introduction

For 2026, the NAEP assessment involves the following components:

1. National assessments in reading and mathematics at grades 4 and 8, and in U.S. history and civics at grade 8;

2. State-by-state and Trial Urban District Assessment (TUDA) assessments in reading and mathematics for public schools at grades 4 and 8;

3. An assessment of mathematics in Puerto Rico for public schools at grades 4 and 8;

4. Pilot assessments in mathematics and reading for public schools at grades 4, 8, and 12;

5. Pilot assessments for Puerto Rico mathematics at grades 4 and 8; and

6. Field trial assessments in mathematics and reading at grades 4 and 8; in U.S. history and civics at grade 8; in Puerto Rico mathematics at grades 4 and 8; and in mathematics and reading pilots at grades 4, 8, and 12.

Below is a summary list of the features of the 2026 sample design.

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1. The alpha¹ samples for grades 4 and 8 public schools and the delta samples for grades 4 and 8 private schools will be used for the operational assessments in reading and mathematics. The alpha samples will also include the Puerto Rico mathematics operational assessments.

2. The beta sample will be used for the national operational U.S. history and civics assessments in public schools at grade 8, and the epsilon sample will be used for U.S. history and civics in private schools at grade 8.

3. The pi samples will be used for the pilot test assessments in mathematics and reading in public schools at grades 4, 8, and 12.

4. As in past NAEP studies, each Trial Urban District Assessment (TUDA) sample will form part of the corresponding state sample, and each state sample will form part of the national sample. There are twenty-six TUDA participants, the same ones as in 2024. The population of schools for a TUDA district consists of those public schools, charter and non-charter, for which the district is responsible for academic accountability.

5. All mathematics and reading operational assessments will be administered using a combination of hybrid device and NAEP-provided device modes as part of a bridge study. In the hybrid device mode, school devices are used if a school qualifies and NAEP-provided devices are used otherwise. Seventy-five percent of the schools in the operational samples will be randomly assigned to the hybrid device mode and twenty-five percent to the NAEP- provided device mode so that each mode is a representative subsample to the extent possible. In the hybrid device random group, the School Technology Survey (STS) will determine if a school qualifies for school devices and if so, school devices will be used. It is assumed that eighty percent of all schools will qualify for school devices. The schools that do not qualify will be assessed using NAEP-provided devices. For the NAEP-provided device random group, while the STS will be completed by all schools, NAEP-provided devices will be used even if the school qualifies for school devices.

6. The operational assessments in U.S. history and civics will be administered using NAEP- provided devices only.

7. The pilot assessments will be administered using hybrid device mode only.

8. The school and student sample sizes for the alpha samples in each state will be similar to 2024.

9. There will be no samples in U.S. territories other than for Puerto Rico at grades 4 and 8.

10. The Department of Defense (DoDEA) schools are expected to be reported as a single jurisdiction. As in past NAEP state-by-state assessments, all DoDEA schools and students will be included in the mathematics and reading operational assessments at grades 4 and 8.

11. There is no National Indian Education Study (NIES). This means less extensive sampling of Bureau of Indian Education (BIE) schools in the alpha samples is required than in 2024 and other years when NIES has been conducted. To ensure sound results for American Indian and Alaska Native (AI/AN) students in reading and mathematics at the national level, at

1 The terminology of alpha, beta, delta, epsilon, and pi is defined in Section III.

grades 4 and 8, BIE students will be sampled at the same rate as students in Oklahoma, the state with the highest proportion of AI/AN population.

12. The sampling rates of private schools at grades 4 and 8 will be like those of 2024. Response rates permitting, this will allow separate reporting for reading and mathematics for Catholic and non-Catholic schools at grades 4 and 8, but no further breakdowns by private school type.

13. The sample sizes of assessed students for these various components are shown in Table 1 (which also shows the approximate numbers of participating schools).

14. In the beta public samples, there will be moderate oversampling of schools with relatively moderate-to-high proportions of Black, Hispanic, and AI/AN students.

15. There will be no oversampling of students within schools for any of the samples.

16. The preliminary 2023-24 Common Core of Data (CCD) serves as the basis for the public school frames. The 2023-24 Private School Universe Survey (PSS) file serves as the basis for the private school frames.

Table 1. Target sample sizes of assessed students, and expected number of participating schools, for 2026 NAEP operational and pilot samples

	Spiral1	Jurisdictions		Students		Total
	Spiral Indic.	States2	Urban districts	Public school students	Private school students
Grade 4
National/state reading	DS	52	26	110,700	2,350	113,050
National/state mathematics	DS	52	26	110,700	2,350	113,050
Puerto Rico	DP	1		4,000		4,000
Total – alpha	2			225,400		225,400
Total – delta	1				4,700	4,700
Typical max. no. students/school				50	50
Average assessed students/school				38	21
Total schools – alpha, delta				5,937	229	6,166
Reading Pilot	NP			3,000		3,000
Mathematics Pilot	NP			6,000		6,000
Puerto Rico Pilot	MP			500		500
Total – pi	2			9,500		9,500
Typical max. no. students/school				50
Average assessed students/school				38
Total schools – pi				257		257
Total number of students grade 4				234,900	4,700	239,600
Total number of schools grade 4				6,194	229	6,423

Table 1. Target sample sizes of assessed students, and expected number of participating schools, for 2026 NAEP operational and pilot samples (Continued)

	Spiral1	Jurisdictions		Students		Total
	Spiral Indic.	States2	Urban districts	Public school students	Private school students
Grade 8
National/state reading	DS	52	26	110,700	2,350	113,050
National/state mathematics	DS	52	26	110,700	2,350	113,050
Puerto Rico	DP	1		4,000		4,000
Total – alpha	2			225,400		225,400
Total – delta	1				4,700	4,700
Typical max. no. students/school				50	50
Average assessed students/school				39	22
Total schools – alpha, delta				5,859	214	6,073
U.S. History	DA			7,200	800	8,000
Civics	DA			7,200	800	8,000
Total - beta	1			14,400		14,400
Total - epsilon	1				1,600	1,600
Typical max. no. students/school				50	50
Average assessed students/school				39	22
Total schools - beta, epsilon				369	72	431
Reading pilot	NP			10,000		10,000
Mathematics pilot	NP			6,000		6,000
Puerto Rico pilot	MP			500		500
Total – pi	2			16,500		16,500
Typical max. no. students/school				50
Average assessed students/school				39
Total schools – pi				434		434
Total number of students grade 8				256,300	6,300	262,600
Total number of schools grade 8				6,661	286	6,947

Table 1. Target sample sizes of assessed students, and expected number of participating schools, for 2026 NAEP operational and pilot samples (Continued)

	Spiral1	Jurisdictions		Students		Total
	Spiral Indic.	States2	Urban districts	Public school students	Private school students
Grade 12
Reading pilot	NP			4,500		4,500
Mathematics pilot	NP			6,000		6,000
Total – pi	1			10,500		10,500
Typical max. no. students/school				50
Average assessed students/school				32
Total schools – pi				328		328
Total number of students grade 12				10,500		10,500
Total number of schools grade 12				328		328
GRAND TOTAL STUDENTS				501,700	11,000	512,700
GRAND TOTAL SCHOOLS				13,183	515	13,698

1 See Table 2 for definitions of the spiral indicators.

2 Includes District of Columbia (DC), DoDEA, and Puerto Rico schools.

2. Assessment Types

The assessment spiral types are shown in Table 2. Four different spirals will be used at grade 4, five different spirals will be used at grade 8, and one spiral will be used at grade 12. Session IDs contain six characters, traditionally. The first two characters identify the assessment “type” (subjects and type of spiral in a general way). Grade is contained in the second pair of characters, and the session sequential number (within schools) in the last two characters. For example, session DS0401 denotes the first grade 4 reading and mathematics operational DBA assessment in a given school.

Table 2. NAEP 2026 assessment types and IDs for operational and pilot assessments

ID	Type	Subjects	Grades	Schools	Comments
DS	Operational/ Bridge	Reading, mathematics	4, 8	Public, Private	All schools in the alpha (except Puerto Rico) and delta samples
DA	Operational/ Bridge	U.S. history and civics	8	Public, Private	All grade 8 schools in the beta and epsilon samples
DP	Operational/ Bridge	Puerto Rico mathematics	4, 8	Public	Puerto Rico alpha samples
NP	Pilot	Reading, mathematics	4, 8, 12	Public	All schools in the pi samples (except Puerto Rico)
MP	Pilot	Puerto Rico mathematics	4, 8	Public	Puerto Rico pi samples

3. Sample Types and Sizes

Similar to past years, we have identified five different types of school samples: alpha, beta, delta, epsilon, and pi. These distinguish sets of schools that will be conducting distinct portions of the assessment.

1. Alpha Samples

These are public school samples for grades 4 and 8. They will be used for the operational/bridge state-by- state assessments in reading and mathematics and contribute to the national samples for these subjects as well. There will be alpha samples for each state, District of Columbia (DC), Department of Defense Education Activity (DoDEA) schools, Bureau of Indian Education (BIE) schools, and Puerto Rico.

The details of the target student sample sizes for the alpha samples are as follows:

1. At each grade, the assessed student target sample size is 3,500 per state. The goal in each state (before considering the contribution of TUDA districts) is to assess 1,750 students for mathematics and 1,750 students for reading. The initial target sample size of students after considering attrition is 4,100 for grade 4 and 4,200 for grade 8.

2. There will be samples for twenty-six TUDA districts. For the six large TUDA districts (New York, Los Angeles, Chicago, Miami-Dade, Clark County, and Houston), the assessed student target sample sizes are three-quarters the size of a state sample (2,625). The target student sample size after considering attrition is 3,075 for grade 4 and 3,150 for grade 8.

3. For the remaining twenty TUDA districts, the assessed student target sample sizes are half the size of a state sample (1,750). The target student sample size after inflation to account for attrition is 2,050 for grade 4 and 2,100 for grade 8.

4. Note that, above, there is a conflict between sample size requirements at the state level, and the TUDA district level. This will be resolved as in previous years: the districts will have the target samples indicated in B and C and reflected in Table 3. For the states that contain one or more of these districts, the target sample size indicated in A (and shown in Table 3) will be used to determine a school sampling rate for the state, which will be applied to the balance of the state outside the TUDA district(s). Thus, the target student sample sizes, shown in Table 3, for states that contain a TUDA district, are only ‘design targets’, and are smaller than the final total sample

size for the state, but larger than the sample for the balance of the state, exclusive of its TUDA districts.

5. In Puerto Rico, the target sample size is 4,800 per grade (grades 4 and 8), with the goal of assessing 4,000 students.

As in past state-by-state assessments, schools with fewer than 20 students in the grade in question will be sampled at a moderately lower rate than other schools (at least half, and often higher, depending upon the size of the school). This is in implicit recognition of the greater cost and burden associated with surveying these schools.

Table 3 shows the target student sample sizes, and the approximate counts of schools to be selected in the alpha samples, along with the school and student frame counts, by state and TUDA districts for grades 4 and 8. The table also identifies the jurisdictions where we take all schools and where we take all students.

Table 4 consolidates the target student (and resulting school) sample size numbers, to show the total target sample sizes in each state, combining the TUDA targets with those for the balance of the state.

Table 3. Grade 4 and 8 school and student frame counts, expected school sample sizes, and initial target student sample sizes for the 2026 state-by-state and TUDA district assessments (Alpha samples)

Jurisdiction	Grade 4					Grade 8
	Schools in frame	Schools in sample	Students in frame	Overall target student sample size		Schools in frame	Schools in sample	Students in frame	Overall target student sample size
Alabama	690	86	55,420	4,100		441	87	54,193	4,200
Alaska	337	141	8,367	4,100		266	110	8,332	4,200
Arizona	1,240	90	81,272	4,100		843	91	80,706	4,200
Arkansas	470	87	35,685	4,100		305	86	36,103	4,200
Bureau of Indian Education	137	10	2,903	241		111	9	2,709	233
California	6,142	87	415,717	4,100		3,108	89	423,872	4,200
Colorado	1,079	91	61,593	4,100		622	90	61,511	4,200
Connecticut	551	87	36,161	4,100		294	86	36,847	4,200
Delaware	118	78	10,321	4,100		70	53	10,859	4,200
District of Columbia	133	92	6,617	4,100		73	73	5,587	4,200	*
DoDEA Schools	90	90	5,828	5,828	**	52	52	4,649	4,649	**
Florida	2,355	85	211,918	4,100		1,366	87	212,036	4,200
Georgia	1,253	83	126,461	4,100		599	85	129,979	4,200
Hawaii	206	89	13,433	4,100		87	56	12,832	4,200
Idaho	405	94	22,495	4,100		243	89	23,456	4,200
Illinois	2,110	91	131,176	4,100		1,421	91	135,786	4,200
Indiana	1,010	86	75,372	4,100		497	86	76,496	4,200
Iowa	600	91	35,752	4,100		350	88	35,912	4,200
Kansas	683	97	33,689	4,100		394	94	34,971	4,200
Kentucky	710	87	48,595	4,100		443	91	46,783	4,200
Louisiana	723	87	52,949	4,100		503	88	51,105	4,200
Maine	309	110	12,499	4,100		190	91	12,561	4,200
Maryland	891	85	65,831	4,100		366	86	64,605	4,200
Massachusetts	934	87	65,639	4,100		497	86	67,617	4,200
Michigan	1,655	90	100,767	4,100		1,110	92	101,891	4,200
Minnesota	993	92	62,668	4,100		732	95	63,522	4,200
Mississippi	399	87	31,926	4,100		268	85	32,212	4,200
Missouri	1,154	95	64,719	4,100		716	94	66,157	4,200

Table 3. Grade 4 and 8 school and student frame counts, expected school sample sizes, and initial target student sample sizes for the 2026 state-by-state and TUDA district assessments (Alpha samples) (Continued)

Jurisdiction	Grade 4					Grade 8
	Schools in frame	Schools in sample	Students in frame	Overall target student sample size		Schools in frame	Schools in sample	Students in frame	Overall target student sample size
Montana	389	128	11,478	4,100		270	102	11,476	4,200
Nebraska	515	101	23,646	4,100		291	95	23,407	4,200
Nevada	449	86	35,200	4,100		199	85	36,039	4,200
New Hampshire	271	103	12,170	4,100		153	80	12,285	4,200
New Jersey	1,347	87	97,325	4,100		789	87	99,542	4,200
New Mexico	441	97	22,010	4,100		244	91	22,449	4,200
New York	2,545	87	181,330	4,100		1,593	87	183,895	4,200
North Carolina	1,526	86	114,540	4,100		810	87	115,405	4,200
North Dakota	264	119	9,308	4,100		184	89	8,866	4,200
Ohio	1,629	88	120,359	4,100		1,093	89	121,300	4,200
Oklahoma	826	95	49,255	4,100		585	94	49,041	4,200
Oregon	770	94	40,401	4,100		425	93	41,429	4,200
Pennsylvania	1,528	85	122,027	4,100		892	86	123,918	4,200
Puerto Rico	542	202	17,891	4,800		378	198	17,208	4,800
Rhode Island	163	87	9,765	4,100		69	58	10,005	4,200
South Carolina	664	85	57,691	4,100		335	85	57,668	4,200
South Dakota	312	119	10,651	4,100		255	101	10,721	4,200
Tennessee	1,005	87	74,928	4,100		591	87	72,246	4,200
Texas	4,760	85	397,573	4,100		2,467	87	401,798	4,200
Utah	660	86	49,133	4,100		280	86	51,269	4,200
Vermont	205	134	5,701	4,100		109	86	5,457	4,200
Virginia	1,117	85	92,047	4,100		381	84	92,883	4,200
Washington	1,286	89	79,786	4,100		645	90	79,590	4,200
West Virginia	381	105	16,939	4,100		183	87	17,883	4,200
Wisconsin	1,065	95	55,916	4,100		654	92	56,888	4,200
Wyoming	174	102	6,846	4,100		83	61	7,109	4,200

Table 3. Grade 4 and 8 school and student frame counts, expected school sample sizes, and initial target student sample sizes for the 2026 state-by-state and TUDA district assessments (Alpha samples) (Continued)

Jurisdiction	Grade 4					Grade 8
	Schools in frame	Schools in sample	Students in frame	Overall target student sample size		Schools in frame	Schools in sample	Students in frame	Overall target student sample size
Albuquerque	102	46	5,476	2,050		46	35	4,966	2,100
Atlanta	56	40	3,977	2,050		27	27	3,660	2,100	*
Austin	77	42	5,420	2,050		19	19	4,691	2,100	*
Baltimore City	110	46	6,045	2,050		84	46	4,979	2,100
Boston	70	50	3,110	2,050		43	43	2,998	2,100	*
Charlotte	117	42	10,665	2,050		50	34	10,490	2,100
Chicago	458	74	22,857	3,075		458	76	23,532	3,150
Clark County, NV	239	63	21,268	3,075		76	56	22,466	3,150
Cleveland	65	65	2,423	2,423	**	64	64	2,392	2,392	**
Dallas	153	43	10,274	2,050		54	36	8,956	2,100
Denver	109	45	6,396	2,050		57	38	5,955	2,100
Detroit	74	46	3,960	2,050		61	45	3,370	2,100
Duval County, FL	129	43	10,304	2,050		66	37	9,166	2,100
Fort Worth	84	43	5,076	2,050		29	29	4,726	2,100	*
Guilford County, NC	70	43	4,964	2,050		25	25	4,840	2,100	*
Hillsborough County, FL	191	42	16,665	2,050		108	42	16,130	2,100
Houston	174	63	14,042	3,075		58	44	10,986	3,150
Jefferson County, KY	96	42	7,238	2,050		42	29	6,551	2,100
Los Angeles	498	65	32,336	3,075		135	62	27,819	3,150
Miami	302	64	24,383	3,075		205	65	25,599	3,150
Milwaukee	111	51	4,943	2,050		81	47	4,216	2,100
New York City	825	66	57,498	3,075		513	65	57,204	3,150
Orange County, FL	171	42	15,331	2,050		83	42	15,584	2,100
Philadelphia	149	46	8,946	2,050		125	45	7,932	2,100
San Diego	119	44	7,477	2,050		35	35	6,150	2,100	*
District of Columbia PS	79	47	3,931	2,050		25	25	2,711	2,100	*

Counts for states do not reflect the oversampling for their constituent TUDA districts.

Target student sample sizes reflect sample sizes prior to attrition due to exclusion, ineligibility, and nonresponse.

• identifies jurisdictions where all schools (but not all students) for the given grade are included in the NAEP sample.

** identifies jurisdictions where all students for the given grade are included in the NAEP sample.

Table 4. Total sample sizes, combining state and TUDA samples

Jurisdiction	Grade 4					Grade 8
	Schools in frame	Schools in sample	Students in frame	Overall target student sample size		Schools in frame	Schools in sample	Students in frame	Overall target student sample size
Alabama	690	86	55,420	4,100		441	87	54,193	4,200
Alaska	337	141	8,367	4,100		266	110	8,332	4,200
Arizona	1,240	90	81,272	4,100		843	91	80,706	4,200
Arkansas	470	87	35,685	4,100		305	86	36,103	4,200
Bureau Of Indian Education	137	10	2,903	241		111	9	2,709	233
California	6,142	188	415,717	8,831		3,108	179	423,872	9,112
Colorado	1,079	126	61,593	5,722		622	120	61,511	5,892
Connecticut	551	87	36,161	4,100		294	86	36,847	4,200
Delaware	118	78	10,321	4,100		70	53	10,859	4,200
District Of Columbia	133	92	6,617	4,100		73	73	5,587	4,410	*
DoDEA Schools	90	90	5,828	5,828	**	52	52	4,649	4,649	**
Florida	2,355	249	211,918	12,034		1,366	246	212,036	12,332
Georgia	1,253	120	126,461	6,021		599	109	129,979	6,182
Hawaii	206	89	13,433	4,100		87	56	12,832	4,200
Idaho	405	94	22,495	4,100		243	89	23,456	4,200
Illinois	2,110	148	131,176	6,460		1,421	149	135,786	6,622
Indiana	1,010	86	75,372	4,100		497	86	76,496	4,200
Iowa	600	91	35,752	4,100		350	88	35,912	4,200
Kansas	683	97	33,689	4,100		394	94	34,971	4,200
Kentucky	710	117	48,595	5,539		443	108	46,783	5,711
Louisiana	723	87	52,949	4,100		503	88	51,105	4,200
Maine	309	110	12,499	4,100		190	91	12,561	4,200
Maryland	891	123	65,831	5,774		366	125	64,605	5,977
Massachusetts	934	132	65,639	5,956		497	125	67,617	6,114
Michigan	1,655	133	100,767	5,989		1,110	133	101,891	6,161
Minnesota	993	92	62,668	4,100		732	95	63,522	4,200
Mississippi	399	87	31,926	4,100		268	85	32,212	4,200
Missouri	1,154	95	64,719	4,100		716	94	66,157	4,200
Montana	389	128	11,478	4,100		270	102	11,476	4,200

Table 4. Total sample sizes, combining state and TUDA samples (Continued)

Jurisdiction	Grade 4					Grade 8
	Schools in frame	Schools in sample	Students in frame	Overall target student sample size		Schools in frame	Schools in sample	Students in frame	Overall target student sample size
Nebraska	515	101	23,646	4,100		291	95	23,407	4,200
Nevada	449	98	35,200	4,693		199	90	36,039	4,729
New Hampshire	271	103	12,170	4,100		153	80	12,285	4,200
New Jersey	1,347	87	97,325	4,100		789	87	99,542	4,200
New Mexico	441	120	22,010	5,120		244	106	22,449	5,364
New York	2,545	125	181,330	5,874		1,593	126	183,895	6,043
North Carolina	1,526	159	114,540	7,640		810	134	115,405	7,841
North Dakota	264	119	9,308	4,100		184	89	8,866	4,200
Ohio	1,629	151	120,359	6,523		1,093	150	121,300	6,509
Oklahoma	826	95	49,255	4,100		585	94	49,041	4,200
Oregon	770	94	40,401	4,100		425	93	41,429	4,200
Pennsylvania	1,528	124	122,027	5,849		892	124	123,918	6,031
Puerto Rico	542	202	17,891	4,800		378	198	17,208	4,800
Rhode Island	163	86	9,765	4,100		69	58	10,005	4,200
South Carolina	664	85	57,691	4,100		335	85	57,668	4,200
South Dakota	312	119	10,651	4,100		255	100	10,721	4,200
Tennessee	1,005	87	74,928	4,100		591	87	72,246	4,200
Texas	4,760	268	397,573	12,965		2,467	209	401,798	13,342
Utah	660	86	49,133	4,100		280	86	51,269	4,200
Vermont	205	134	5,701	4,100		109	86	5,457	4,200
Virginia	1,117	85	92,047	4,100		381	84	92,883	4,200
Washington	1,286	89	79,786	4,100		645	90	79,590	4,200
West Virginia	381	105	16,939	4,100		183	87	17,883	4,200
Wisconsin	1,065	137	55,916	5,786		654	132	56,888	5,988
Wyoming	174	102	6,846	4,100		83	61	7,109	4,200
Total	52,211	6,117	3,589,689	267,046		29,925	5,540	3,623,066	272,642

Sample sizes for each state reflect the samples in the TUDA districts within the state.

• identifies jurisdictions where all schools (but not all students) for the given grade are included in the NAEP sample.

** identifies jurisdictions where all students for the given grade are included in the NAEP sample.

Stratification

Each state and grade will be stratified separately but using a common approach in all cases. TUDA districts will be separated from the balance of their state, and each part stratified separately. The first level of stratification will be based on urban-centric type of location. This variable has 12 levels (some of which may not be present in a given state or TUDA district), and these will be collapsed so that each of the resulting location categories contains at least 10 percent of the student population (13 percent for large TUDA districts and 20 percent for small TUDA districts).

Within each of the resulting location categories, schools will be assigned a minority enrollment status. This is based on the two race/ethnic groups that are the second and third most prevalent within the location category. If these groups are both low in percentage terms, no minority classification will be used. Otherwise, three (or occasionally four) equal-sized groups (generally high, medium, and low minority) will be formed based on the distribution across schools of the two minority groups.

Within the resulting location and minority group classes (of which there are likely to be from two to twenty-three, depending upon the jurisdiction), schools will be sorted by a measure derived from school level results from the most recent available state achievement tests at the relevant grade. In general, mathematics test results will be used, but where these are not available, reading results will be used. In the few states that do not have math or reading tests at grades 4 and 8 (or where we are unable to match the results to the NAEP school frame), instead of achievement data, schools will be sorted using a measure of socio-economic status. This is the median household income of the 5-digit ZIP Code area where the school is located, based on the 2023 ACS (5-year) data. For BIE and DoDEA schools neither achievement data nor income data are available, so grade enrollment is used in these cases.

Once the schools are sorted in a serpentine fashion by location class, minority enrollment class, and achievement data (or household income/grade enrollment), a systematic sample of schools will be selected using a random start. Schools will be sampled with probability proportional to size.

2. Beta Sample

The beta sample comprises the national public school sample at grade 8 that will be used for the national operational U.S. history and civics assessments. The sample will be nationally representative, selected to have minimal overlap with the alpha sample schools at the same grade. The number of students targeted for selection per school will be 50.

In order to increase the likelihood that the results for AI/AN students can be reported for this sample, we will oversample public schools with a relatively high-AI/AN student population. That is, a public school with at least 5 AI/AN students and at least 5 percent AI/AN enrollment will be given four times the chance of selection of a public school of the same size with a lower AI/AN percentage. For all other schools, whenever there are at least 10 Black or Hispanic students enrolled and the combined Black and Hispanic enrollment at least 15 percent, the school will be given twice the chance of selection of a public school of the same size with a lower percentage of these two groups. This approach is effective in increasing the sample sizes of AI/AN, Black, and Hispanic students without inducing undesirably large design effects on the sample, either overall or for particular subgroups.

Stratification

The beta sample will have an implicit stratification, using a hierarchy of stratifiers and a serpentine sort. The highest level of the hierarchy is high/low AI/AN status. The second stratifier is Census division (10 categories: the usual 9 plus California as a separate category). Some of the Census divisions within the high AI/AN stratum will be collapsed with neighboring Census divisions (this will occur if the expected school sample size within the cell is less than 4.0).

The next stratifier in the hierarchy is type of location, which has twelve categories. Within the high AI/AN stratum, the cells will likely be too small to further stratify by type of location. Within the low AI/AN stratum, many of the type of location strata nested within Census divisions will be collapsed with neighboring type of location cells (this will occur if the expected school sample size within the cell is less than 4.0).

These geographic strata will be subdivided into high/low Black and Hispanic substrata. If the expected initial sample size in a Black/Hispanic substratum is less than 8.0, it will be left as is. If the expected sample size is greater than or equal to 8.0, then it will be subdivided into up to four substrata (two for expected sample size up to but less than 12.0, three for expected sample size up to but less than 16.0, and four for expected sample size greater than or equal to 16.0). For the high Black/Hispanic substrata, the subdivision will be by percentage Black and Hispanic. For the low Black/Hispanic substrata, the subdivision will be by state or groups of contiguous states.

Within these substrata, the schools are to be sorted by school type (public, BIE, DoDEA) and median household income from the 2023 5-year ACS (using a serpentine sort within the school type substrata), except in California where state achievement data will be used.

3. Delta Samples

These are the private school samples at grades 4 and 8 for conducting the operational study assessments in reading and mathematics. The sample sizes are large enough to report results by Catholic and non- Catholic at grades 4 and 8 (of course participation rate standards must be met). Approximately half the sample at each grade will be from Catholic schools. The grade 8 delta samples will be selected to have minimum overlap with the grade 4 delta sample. The number of students targeted per school will be 50 at each grade.

Stratification

The private schools are to be explicitly stratified by private school type (Catholic/Other). Within each private school type, implicit stratification will be by Census region (4 categories), type of location (12 categories), race/ethnicity composition, and enrollment size. In general, where there are few or no schools in a given stratum, categories will be collapsed together, always preserving the private school type.

4. Epsilon Sample

The epsilon sample comprises the national private school sample at grade 8 that will be used for the national operational U.S. history and civics assessments. However, in contrast to the beta sample, there will be no oversampling of high AI/AN or high Black and Hispanic schools. The same stratification variables will be used as for the delta samples. The epsilon sample schools at grade 8 will have minimum

overlap with the delta grade 8 sample schools which, given the respective sample sizes, means that no schools will be selected for both the delta and epsilon samples at grade 8. The number of students targeted per school will be 50.

5. Pi Samples

These are the public-school samples at grades 4, 8, and 12 for conducting the pilot test assessments in reading and mathematics. The pi sample will also include the pilot assessments for Puerto Rico mathematics at grades 4 and 8. Schools selected in the alpha or beta samples will be removed from the pilot school frames at all three grades. The number of students targeted per school will be 50 for schools in the reading and mathematics pilot and 25 for schools in the Puerto Rico mathematics pilot.

Stratification

The pilot samples will have an implicit stratification similar to the beta samples, using a hierarchy of stratifiers and a serpentine sort. The highest level of the hierarchy is high/low AI/AN status. The second stratifier is Census division (10 categories: the usual 9 plus California as a separate category). Some of the Census divisions within the high AI/AN stratum will be collapsed with neighboring Census divisions (this will occur if the expected school sample size within the cell is less than 4.0).

The next stratifier in the hierarchy is type of location, which has twelve categories. Within the high AI/AN stratum, the cells will likely be too small to further stratify by type of location. Within the low AI/AN stratum, many of the type of location strata nested within Census divisions will be collapsed with neighboring type of location cells (this will occur if the expected school sample size within the cell is less than 4.0).

These geographic strata will be subdivided into high/low Black and Hispanic substrata. If the expected initial sample size in a Black/Hispanic substratum is less than 8.0, it will be left as is. If the expected sample size is greater than or equal to 8.0, then it will be subdivided into up to four substrata (two for expected sample size up to but less than 12.0, three for expected sample size up to but less than 16.0, and four for expected sample size greater than or equal to 16.0). For the high Black/Hispanic substrata, the subdivision will be by percentage Black and Hispanic. For the low Black/Hispanic substrata, the subdivision will be by state or groups of contiguous states.

Within these substrata, the schools are to be sorted by school type (public, BIE, DoDEA) and median household income from the 2023 5-year ACS (using a serpentine sort within the school type substrata) except in California where state achievement data will be used.

For Puerto Rico, the sampling frame of schools will be stratified using the type of location variable. No oversampling of schools or students will occur in the pilot tests in Puerto Rico. Schools will be selected with probabilities proportionate to size.

6. Field Trial Samples

Prior to the main NAEP data collection for 2026, field trial assessments will take place in fall 2025 to test the systems and data collection processes planned for the operational and pilot assessments at grades 4, 8, and 12. The field trial assessments will take place in 18 U.S. mainland and two Puerto Rico schools.

4. New Schools

To compensate for the fact that files used to create the NAEP school sampling frames are at least two years out of date at the time of frame construction, we will supplement the alpha, beta, delta, and epsilon samples with new school samples at each grade.

The new school samples will be drawn using a two-stage design. At the first stage, a minimum of ten school districts (in states with at least ten districts) will be selected from each state for public schools, and ten Catholic dioceses will be selected nationally for the private schools. The sampled districts and dioceses will be asked to review lists of their respective schools and identify new schools. Frames of new schools will be constructed from these updates, and new schools will be drawn with probability proportional to size using the same sample rates as their corresponding original school samples.

The school sample sizes in the above tables do not reflect new school samples.

5. Substitute Samples

Substitute samples will be selected for each of the beta, delta, and epsilon samples. The substitute school for each original will be the next “available” school on the sorted sampling frame, with the following exceptions:

1. Schools selected for any NAEP samples will not be used as substitutes.

2. Private schools whose school affiliation is unknown will not be used as substitutes. Also, unknown affiliated private schools in the original samples will not get substitutes.

3. New schools will not get substitutes.

4. A school can be a substitute for one and only one sample. (If a school is selected as a substitute school for grade 8, for example, it cannot be used as a substitute for grade 4.)

5. A public-school substitute will always be in the same state as its original school.

6. A private-school substitute will always have the same affiliation as its original school.

6. Contingency Samples

The districts that are taking part in the TUDA program are volunteers. Thus, it is possible that at some point over the next few months, a given district might choose to opt out of the TUDA program for 2026. However, it is not acceptable for all schools in such a district to decline NAEP, as then the state estimates will be adversely affected. Thus, to deal with this possibility, in each TUDA district, subsamples of the alpha sample schools will be identified as contingency samples. In the event that the district withdraws from the TUDA program prior to the selection of the student sample, all alpha sampled schools from that district will be dropped from the sample, with the exception of those selected in the contingency sample. The contingency sample will provide a proportional representation of the district, within the aggregate state sample. Student sampling in those schools will then proceed in the same way as for the other schools within the same state.

7. Student Sampling

Students within the sampled schools will be selected with equal probability. The student sampling parameters vary by sample type (alpha, beta, delta, epsilon, and pi) and grade as described below. Prior to sampling, students will be sorted by gender, race, last name, first name, and middle name.

Alpha Sample, Grades 4 and 8 Schools (Except Puerto Rico)

1. All students, up to 52, will be selected.

2. If the school has more than 52 students, a systematic sample of 50 students will be selected. In

some schools, the school may be assigned more than one ‘hit’ in sampling. In these schools we will select a sample of size 50 times the number of hits, taking all students if this target is greater than or equal to 50/52 of the total enrollment.

Alpha Sample, Puerto Rico Grades 4 and 8

1. All students, up to 26, will be selected.

2. If the school has more than 26 students, a systematic sample of 25 students will be selected.

Delta Samples, Grades 4 and 8

1. All students, up to 52, will be selected.

2. If the school has more than 52 students, a systematic sample of 50 students will be selected.

Beta Sample, Grade 8

1. All students, up to 52, will be selected.

2. If the school has more than 52 students, a systematic sample of 50 students will be selected.

Epsilon Sample, Grade 8

1. All students, up to 52, will be selected.

2. If the school has more than 52 students, a systematic sample of 50 students will be selected.

Pi Samples, Grades 4 and 8 (Except Puerto Rico)

1. All students, up to 52, will be selected.

2. If the school has more than 52 students, a systematic sample of 50 students will be selected.

Pi Samples, Puerto Rico Grades 4 and 8

1. All students, up to 26, will be selected.

2. If the school has more than 26 students, a systematic sample of 25 students will be selected.

8. Weighting Requirements

The Operational Reading and Mathematics Assessments, Grades 4 and 8

The exact weighting requirements for these samples have yet to be determined. One likely possibility is that three sets of student weights will be required – for assessments using school device mode alone, NAEP-provided device mode alone, and school/NAEP-provided device modes combined. The samples will have student weights for each subject (reading and mathematics) applied to reflect probabilities of selection, school and student nonresponse, any trimming, and the random assignment to the subject.

There will be separate replication schemes by grade and public/private. Weights will also be derived for the Puerto Rico assessment at grades 4 and 8.

The Operational U.S. History and Civics Assessment, Grade 8

Since the assessments for U.S. history and civics will be administered using only NAEP-provided devices, only one set of student weights will be computed. The weights will reflect probabilities of selection, school and student nonresponse, any trimming. There will be separate replication schemes by public/private.

School Weights

In addition to student weights, each operational sample described above will have a set of school weights to provide secondary users a means to analyze data at the school level. Each sample will have a single set of school weights for each subject (reading and mathematics, or U.S. history and civics) applied to reflect probabilities of selection, school nonresponse, any trimming, and a small-school adjustment to account for schools too small to do both subjects associated to their respective samples. There will be separate replication schemes by public/private.

Pilot Tests for Reading and Mathematics, Grades 4, 8, and 12

As is standard practice, only preliminary weights will be provided for these assessments. The sample weights will reflect probabilities of selection, and the random assignment to the particular subject.

Field Trial Samples

No weights will be provided for the field trial samples.