Lessons learned from the 2025 Algebra I STAAR EOC

Aaron Daffern
2 hours ago
6 min read

Using a modified version of the statewide item analysis report, I examined the readiness standards that had less than 60% mastery. Each standard has both an analysis of the items themselves to infer what made them so difficult and instructional implications for educators to ensure a more successful 2026 STAAR test.

Standard	# of items	% mastery
A.11B	2	35.5
A.3D	2	38.5
A.5C	2	42
A.7C	2	45.5
A.2I	2	50
A.5A	2	50
A.6A	2	51
A.2A	2	53
A.9C	2	53
A.8A	2	55.5
A.3B	2	56
A.9D	2	56.5
A.10E	2	57.5

Access the slide deck here.

A.11B - 35.5% overall mastery

simplify numeric and algebraic expressions using the laws of exponents, including integral and rational exponents

#28 - 24% full credit; 31% partial credit; 45% no credit

#48 - 31% correct

Analysis

The negative exponent in the denominator of #28 increases the complexity
Students could have solved using negative exponents and product of powers or simply the quotient of powers
For #48, 33% chose B (either added exponents 3+2) or forgot the extra y
Students had to apply three rules (negative exponents, power of a power, multiplication of powers) to solve
Both problems included negative exponents

Instructional Implications

Show how the expressions could be simplified using more than one sequence (if applicable)

A.3D - 38.5% overall mastery

graph the solution set of linear inequalities in two variables on the coordinate plane

#10 - 49% correct

#30 - 24% full credit; 8% partial credit; 67% no credit

Analysis

For #10, 22% chose A (correct line, incorrect solution set)
Students could have converted to slope-intercept form or tested 0 as the x and y to graph the equation
⅔ of the students got 0 points on #30
Students have to select “Solution Set” to trigger the shading

Instructional Implications

Have students test the origin (0, 0) to evaluate whether or not it’s in the solution set
Practice using the graphing tool on CambiumGive students range and direction of graph and have them sketch a graph

Watch the full walkthrough of all 50 items on the 2025 Algebra I STAAR EOC below.

A.5c - 42% overall mastery

solve systems of two linear equations with two variables for mathematical and real-world problems

#11 - 52% correct

#24 - 32% correct

Analysis

Both problems were set up for students to easily use substitution
#24 asked students to describe the solution rather than to find the solution
35% chose B, most likely finding one correct solution but not considering more than one solution

Instructional Implications

Students should be familiar with the meaning of non-traditional statements when using substitution or elimination (e.g., 24 = 24)
Before relying on one strategy (e.g., graphing), students should consider all strategies to find the most efficient

A.7C - 45.5% overall mastery

determine the effects on the graph of the parent function f(x) = x^2 when f(x) is replaced by af(x), f(x) + d, f(x - c), f(bx) for specific values of a, b, c, and d

#12 - 41% correct

#39 - 36% full credit; 27% partial credit; 37% no credit

Analysis

Both problems included a horizontal shift [g(x) = f(x-h)]
For #12, 30% of students chose A (misinterpreted shift)
#39 involved both a vertical and horizontal shift

Instructional Implications

Horizontal movement is not intuitive f(x) = a(x - h)^2 + k
Graphing both f(x) and g(x) would show both shifts
The format of the vertex form [f(x) = a(x-h)^2 + k] will be used in many other functions to explain transformations

A.2I - 50% overall mastery

write systems of two linear equations given a table of values, a graph, and a verbal description

#4 - 66% correct

#34 - 34% correct

Analysis

The graph on #4 allowed students to potentially use substitution
No equation was given for #34, students had to decipher using the formula for perimeter and the verbal description
The description of the second equation (y is 6 more than twice the width, x) was itself challenging
39% chose B (didn’t double length and width)

Instructional Implications

Generating equations from verbal descriptions increase the rigor
Utilize equations from geometric situations (e.g., area, perimeter) to challenge students

A.5A - 50% overall mastery

solve linear equations in one variable, including those for which the application of the distributive property is necessary and for which variables are included on both sides

#29 - 58% correct

#46 - 42% correct

Analysis

Both problems involved fractions
Students might have struggled eliminating the different denominators for #46
#46 required distributing twice
30% chose B (only distributed first term on each side)

Instructional Implications

Spend time simplifying fractions on both sides with different denominators
Use substitution to verify the solution

A.6A - 51% overall mastery

determine the domain and range of quadratic functions and represent the domain and range using inequalities

#5 - 42% correct

#32 - 60% correct

Analysis

No visual support was given for #5, students could have solved by graphing or changing into vertex form
33% chose A (correct vertex, wrong direction)
#32 included a truncated graph, though that didn’t cause much confusion

Instructional Implications

Practice ways of identifying features of quadratic functions without graphing (e.g., vertex form)
Identifying the sign of the leading coefficient can eliminate answer choices

A.2A - 53% overall mastery

determine the domain and range of a linear function in mathematical problems; determine reasonable domain and range values for real-world situations, both continuous and discrete; and represent domain and range using inequalities

#16 - 48% correct

#37 - 58% correct

Analysis

Both discrete and continuous data were used
For #16, 31% chose B (continuous rather than discrete)
For #37, 25% chose C (range rather than domain)

Instructional Implications

Continue to equate domain with x and the independent variable
Continue to equate range with y and the dependent variable
For practice, have students describe scenarios in which discrete data would be more appropriate than continuous

A.9C - 53% overall mastery

write exponential functions in the form f(x) = abx (where b is a rational number) to describe problems arising from mathematical and real-world situations, including growth and decay

#18 - 65% correct

#47 - 41% correct

Analysis

Students had less difficulty calculating the rate (#18) than interpreting it (#47)
The a term was evident in both problems
For #47, 33% chose A (incorrect rate)
#47 did not explicitly mention exponential or compound interest

Instructional Implications

Reinforce standard form (y = ab^x) and, in interest problems, how to find the b rate (1 + r)
Review the difference between 0.5% and 0.5

A.8A - 54% overall mastery

solve quadratic equations having real solutions by factoring, taking square roots, completing the square, and applying the quadratic formula

#26 - 56% correct

#36 - 34% full credit; 42% partial credit; 25% no credit

Analysis

Neither problem was given in standard form (y=ax^2 + bx + c)
For #26, students had to apply the distributive property and interpret the solutions to solve
For #36, students had to take a square root and consider both positive and negative solutions for full credit

Instructional Implications

Have students solve equations using two methods at a minimum to increase flexibility
Spend time evaluating problems to identify the most efficient strategy

A.3B - 565% overall mastery

calculate the rate of change of a linear function represented tabularly, graphically, or algebraically in context of mathematical and real-world problems

#13 - 48% correct

#50 - 64% correct

Analysis

Students might have been unfamiliar with the formal language used in #13 (i.e., rate of change of y with respect to x)
21% chose A and 21% chose B, focusing on the only available coefficient
The graphical representation in #50 provided additional scaffolding
20% chose B (x/y)

Instructional Implications

Refer back to direct variation (k = y/x)
Use formal language (y with respect to x) to increase student awareness

A.9D - 56.5% overall mastery

graph exponential functions that model growth and decay and identify key features, including y- intercept and asymptote, in mathematical and real-world problems

#2 - 79% correct

#33 - 34% correct

Analysis

Little difficulty with #2
Students have never been asked to graph an exponential function on STAAR before (#33)
Students had to select the correct graph and be able to identify two points (e.g, x = 0 and x = 1) to graph correctly

Instructional Implications

Graph exponential functions on paper given a table of values or equation
Practice using the graphing tool on Cambium

A.10E - 57.5% overall mastery

factor, if possible, trinomials with real factors in the form ax^2 + bx + c, including perfect square trinomials of degree two

#20 - 41% correct

#44 - 58% full credit; 31% partial credit; 11% no credit

Analysis

#20 only asked for one factor, eliminating the possibility of reverse engineering the correct answer through the distributive property
34% chose B (likely made a sign error when factoring)
Almost 90% of students got at least 1 point on #44

Instructional Implications

When factoring, remove all answer choices or only show one factor to eliminate answering by the distributive property
Remind students to first factor out a common factor (if possible) to simplify the process