aimswebPlus Reading

Letter Word Sounds Fluency


Technology, Human Resources, and Accommodations for Special Needs

Service and Support

Purpose and Other Implementation Information

Usage and Reporting

Initial Cost:

aimswebPlus is a subscription-based tool. There are three subscription types available for customers*:

  • aimswebPlus Complete is $8.50 per student and includes all measures.
  • aimswebPlus Reading is $6.50 per student and includes Early Literacy and Reading measures.
  • aimswebPlus Math is $6.50 per student and includes Early Numeracy and Math measures.


*Current aimsweb customers upgrading to aimswebPlus receive a $2/student discount off the subscription.        


Replacement Cost:

$8.50 per student per year.

Annual license fee subject to change.


Included in Cost:

Complete Kit: aimswebPlus is an online solution that includes digital editions of training manuals and testing materials within the application.


Technology Requirements:

  • Computer or tablet
  • Internet connection


Training Requirements:

  • Less than 1 hour of training


Qualified Administrators:

  • Paraprofessionals
  • Professionals



Test accommodations that are documented in a student’s Individual Education Plan (IEP) are permitted with aimswebPlus. However, not all measures allow for accommodations.


Letter Word Sounds Fluency is an individually administered, timed test that employs strict time limits to generate rate-based scores. As such, valid interpretation of national norms, which are an essential aspect of decision-making during benchmark testing, depend on strict adherence to the standard administration procedures.


The following accommodations are allowed for Letter Word Sounds Fluency during screening and progress monitoring:

  • Enlarging test forms
  • Modifying the environment (e.g., special lighting, adaptive furniture)

Where to Obtain:



San Antonio Office

19500 Bulverde Road, #201

San Antonio, TX, 78259

Phone Number:


Access to Technical Support:

Pearson provides phone and email-based support, as well as a user group forum that facilitates the asking and answering of questions.


aimswebPlus is a brief assessment system for screening and monitoring reading and math skills for all students in Kindergarten through Grade 8. Normative data were collected in 2013–14 on a combination of fluency measures that are sensitive to growth as well as new standards-based assessments of classroom skills. The resulting scores and reports inform instruction and help improve student performance.


Letter Word Sounds Fluency is individually administered, with a teacher/examiner recording student data during the test session. Once testing is complete, summary and detailed reports for students, classrooms, and districts can be generated immediately.


Assessment Format:

  • Individual
  • Computer-administered*

*Examiners use digital record form.


Administration Time:

  • 1 minute per student


Scoring Time:

  • Scoring is automatic


Scoring Method:

  • Calculated automatically


Scores Generated:

  • Percentile Score
  • Raw Score




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Justify the appropriateness of each type of reliability reported:

Alternate-form reliability, where equivalent forms are administered close together in time, is highly appropriate for progress monitoring CBM measures because it shows the consistency of scores from independently timed administrations with different content. Internal consistency reliability is not appropriate for speeded CBM measures.

The stability coefficient, where equivalent forms are administered with an interval of several months, reflects additional measurement error due to true change over time. As a result, these reliabilities are generally lower. The alternate-form stability coefficient is based on correlations between fall-winter and winter-spring benchmark scores.


Describe the sample characteristics for each reliability analysis conducted:

The concurrent alternate-form reliability sample is based on 10 schools from across the U.S. representing each of three SES levels (described above). Participating schools administered the alternate forms to all Kindergarten students in the school, with few exceptions for moderate to severe intellectual disabilities. Each student completed 2 of 3 alternate forms with forms administered in pairs: 1,2; 1,3; and 2, 3.  The number of students completing each pair ranged from 90–217.


Describe the analysis procedures for each reported type of reliability:

Pearson correlation coefficients of the scores from alternate forms.

Type of Reliability

Age or Grade



Confidence Interval

Alternate Form (concurrent)


90- 217



(alternate forms across season)







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Describe and justify the criterion measures used to demonstrate validity:

Two validity studies are reported: a concurrent study and a predictive study of Letter-Word Sounds Fluency (LWSF) with Word Reading Fluency (WRF). WRF, like LWSF is an aimswebPlus timed fluency measure. However, unlike LWSF which measures the students fluency and proficiency saying letter sounds and decoding CVC words, WRF measures fluency and proficiency with wide range of sight words.  The content of WRF does not overlap with LWSF. Moreover, the validity coefficients reported are based on the initial administration of each measure in the aimswebPlus benchmark system. As such, there is no practice/exposure effect impacting the validity coefficients.


Describe the sample characteristics for each validity analysis conducted:



Word Reading Fluency

(N = 2000)

Oral Reading Fluency

(N = 2000)

Gender (%)







Race/ethnicity (%)

    African American












ELL (%)



Free/reduced lunch

    68%–100% (school %)



    34%–67% (school %)



    0%–33% (school %)




Describe the analysis procedures for each reported type of validity:

Predictive validity is based on winter LWSF scores and spring WRF scores. LWSF is first used in aimswebPlus benchmarking in the winter of Kindergarten; whereas WRF is introduced in the spring. The concurrent correlation is based on spring LWSF and WRF scores.


Type of Validity

Age or Grade

Test or Criterion



Confidence Interval

Concurrent criterion-related


Word Reading Fluency (WRF)




Predictive criterion-related







Describe the degree to which the provided data support the validity of the tool:

Letter Word Sounds Fluency (LWSF) is designed to measure fluency making letter sounds, making the sounds of two-letter combinations, and reading aloud consonant-vowel-consonant (CVC) words, a foundational skill important in the developmental progression from letter-sound correspondence to oral word reading. These validity studies support the interpretation of LWSF scores as foundational for success in the more advanced early literacy skills. Furthermore, they demonstrate that performance on Letter Word Sounds Fluency has a strong relationship with initial winter letter sounds and word building skills.

Bias Analysis Conducted


Have additional analyses been conducted to establish whether the tool is or is not biased against demographic subgroups (e.g., students who vary by race/ethnicity, gender, socioeconomic status, students with disabilities, English language learners)?

Bias Analysis Method: No qualifying evidence provided.


Subgroups Included: No qualifying evidence provided.


Bias Analysis Results: No qualifying evidence provided.

Sensitivity: Reliability of the Slope

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Describe the sample used for analyses, including size and characteristics:

The sample consisted of 1,441 Kindergarten students below the 25th national percentile on the fall Letter-Word Sounds Fluency (LWSF) benchmark and who were assigned a reading performance goal and receiving frequent progress monitoring with LWSF. All progress monitoring schedules were at least 20 weeks in duration during the 2016–17 school year.


Describe the frequency of measurement:

The interval between the first and last administration was a minimum of 10 weeks. Students with fewer than 20 weeks of progress monitoring were excluded from the sample. Most administrations occurred weekly, with a small percentage conducted twice monthly.

Number of Weeks Between First and Last Progress Monitoring Administration


Quartile 1


Quartile 3








Describe reliability of the slope analyses conducted with a population of students in need of intensive intervention:

Each student’s progress monitoring administrations were sequenced by date and divided into two groups: odd numbered administrations (e.g., 1,3,5, etc.) and even numbered administrations (e.g., 2,4,6, etc.) Linear regression was used to compute the slope for each student by group. The following model was used:

Scorei = Intercept + Datei

where Date is the amount of time since the start of progress monitoring and i ranges from 1 to the number of administrations.

The correlation between odd-group and even-group slopes across all students was computed and converted to a split-half reliability coefficient using the Spearman-Brown Formula: 2r/(1+r).

Type of Reliability

Age or Grade



Confidence Interval







Sensitivity: Validity of the Slope

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Describe and justify the criterion measures used to demonstrate validity:

Word Reading Fluency (WRF) served as the criterion measure.     

WRF measures proficiency and fluency reading sight words. It is a timed 1 minute measure and is an appropriate criterion measure for LWSF because it builds directly on a student’s proficiency with using letter sounds and building simple CVC words. Word reading skills is also what most of kindergarten literacy instruction builds towards.

WRF is first used in aimswebPlus in the spring Kindergarten benchmark. Thus, there is no overlapping practice or exposure effect of WRF with LWSF.


Describe the sample used for analyses, including size and characteristics:

The sample is the same as that used to compute the reliability of the slope.


Describe predictive validity of the slope of improvement analyses conducted with a population of students in need of intensive intervention:

Spring benchmark WRF scores were regressed onto the Winter to Spring PM slope for LWSF and the Winter LWSF benchmark scores. Including Winter LWSF scores controls for differences in initial performance, thus removing its effect on the relationship between slope and outcome. Standardized regression coefficients and associated standard errors are reported in the table below.

Model 1a: WRF Spring Score = Intercept + LWSF slope + LWSF Winter Score

Type of Validity

Age or Grade

Test or Criterion



Confidence Interval








Describe the degree to which the provided data support the validity of the tool:

These results support the validity of the inference that growth in the LWSF score results in greater proficiency with general word reading skills because Winter to Spring growth in the LWSF construct contributes to higher criterion scores in the Spring. Because WRF is different in content from the LWSF measure; but similar in format, one would expect a moderate correlation between LWSF growth and Spring criterion performance. Therefore, moderate correlations such as these are good supporting evidence.

Alternate Forms

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Describe the sample for these analyses, including size and characteristics:

The sample consisted of 6,732 students from 281 schools each with a reading performance goal and a progress monitoring schedule who scored at or below the 30th national percentile on the spring LWSF benchmark form.


Evidence that alternate forms are of equal and controlled difficulty or, if IRT based, evidence of item or ability invariance:

Each student completed at least one of the alternate LWSF PM forms within a window from 5 to 35 days after benchmark testing. Forms were randomly assigned to students. Because the test interval was fairly brief, and students were randomly assigned to forms, comparability is based on a direct comparison of the sample means. Our prior research showed that many Kindergarten students are not ready for a task that involves saying letter sounds and decoding CVC words in the fall of Kindergarten. The research also shows that most students have mastered the skill by the spring of Kindergarten. Thus, the optimal time frame to measure this skill is from the winter to spring of Kindergarten.

The average performance on the forms, administered in a 30-day window is the basis of form comparability. To demonstrate comparability, we provide the effect size as the mean difference between each form and the average difficulty across all forms in standard deviations units. The means ES is 0.08, and all 10 effect sizes are below 0.30, which is considered small.

Comparability of the entire set of 10 forms is also summarized using analysis of variance where Form is treated as a fixed factor. The results indicate that Form accounts for only 0.89% of the total score variance.  This is a very small percent and will have a trivial effect on the growth slope over the 10 or so administrations that are common for progress monitoring.


Number of alternate forms of equal and controlled difficulty:

Ten alternate forms were evaluated. LWSF has 10 PM forms because it is designed to be used to measure progress over one-half of a school year. 

Decision Rules: Setting and Revising Goals

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Specification of validated decision rules for when goals should be set or revised:

To get the most value from progress monitoring, aimswebPlus recommends the following: (1) establish a time frame, (2) determine the level of performance expected, and (3) determine the criterion for success.  Typical time frames include the duration of the intervention or the end of the school year. An annual time frame is typically used when IEP goals are written for students who are receiving special education services. For example, aimswebPlus goals can be written as follows: In 34 weeks, the student will compare numbers and answer computational problems to earn a score of 30 points on Grade 4 Number Sense Fluency forms.

aimswebPlus provides several ways to define a level of expected performance. The goal can be based on:

●     well-established performance benchmarks that can be linked to aimswebPlus measures via national percentiles (e.g., the link to state test performance levels) or total score (e.g., word read per minute in Grade 2);

●     a national performance norm benchmark (e.g., the 50th national percentile is often used to indicate on-grade level performance);

●     a local performance norm benchmark;

●     or an expected or normative rate of improvement (ROI), such as the 85th national student growth percentile.

To use this last method (student growth percentile), the user begins by selecting the measure and baseline score, the goal date, the monitoring frequency (default is weekly), and a tentative goal score. The system automatically labels the ambitiousness of the goal as Insufficient (SGP below 50), Closes the Gap (SGP between 50 and 85), Ambitious (86 to 97), or Overly Ambitious (above 97). The user can then adjust the goal (or the goal date) in light of this feedback.

For students in need of intensive intervention, aimswebPlus recommends setting performance goals that represent rates of growth between the 86th and 97th SGP (Ambitious). An SGP of 86 represents a growth rate achieved by just 15% of the national sample, which is why it is considered ambitious. However, it is reasonable to expect significantly higher than average growth when implementing effective, intensive intervention.

If the goal is set according to a benchmark based on raw scores or national or local norms, the aimswebPlus system still labels the ambitiousness of the goal in one of the four levels described above. If the goal corresponds to an Insufficient or Overly Ambitious rate of growth, users are advised to consider adjusting the goal. However, the user ultimately determines what growth rate is required on an individual basis.

With respect to the decision to revise a goal, aimswebPlus provides empirically-based feedback about the student’s progress relative to the initial goal using the statistical tool described in our response to question B5 below. If the projected score at the goal date is fully Above Target (i.e., the 75% confidence interval for the student’s projected score at the goal date is entirely above the goal score), we recommend that the user consider raising the goal if the goal date is at least 12 weeks out. Otherwise, we recommend not changing the goal. On the other hand, if the upper end of the confidence interval on the projected score lies Below Target, we recommend either changing the intervention, increasing its intensity, or lowering the goal if the initial goal was Overly Ambitious.


Evidentiary basis for these rules:

As described above, users have flexibility in the method they use to set and revise goals in aimswebPlus. The SGP-based labeling of goals as Overly Ambitious, Ambitious, Closes the Gap, or Insufficient is intended to assist the user in choosing a goal, but is not an automatic goal-setting system. Likewise, the analytical system that generates a confidence interval for the student’s predicted performance at the goal date helps the user manage progress monitoring but does not make a decision about revising the goal. Certainly, a decision to lower a goal would rely primarily on the educator’s judgment, since the first consideration would be to change the intervention. No experiment has been conducted in which the aimswebPlus information related to setting and revision goals was provided for some students receiving intensive intervention but not others

Decision Rules: Changing Instruction

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Specification of validated decision rules for when changes to instruction should be made:

aimswebPlus applies a statistical procedure, based on linear regression, to the student’s progress monitoring scores in order to provide empirically-based guidance about whether the student is likely to meet, fall short of, or exceed his/her goal. The calculation procedure (presented below) is fully described in the aimswebPlus Progress Monitoring Guide (Pearson, 2017). aimswebPlus users will not have to do any calculations—the online system does this automatically.

The decision rule is based on a 75% confidence interval for the student’s predicted score at the goal date. This confidence interval is student-specific and takes into account the number and variability of progress monitoring scores and the duration of monitoring. Starting at the sixth week of monitoring (when there are at least four monitoring scores), the aimswebPlus report following each progress monitoring administration includes one of the following statements:

A.  Below Target. Projected to not meet the goal. This statement appears if the confidence interval is completely below the goal score.

B.  Above Target. Projected to meet or exceed the goal.  This statement appears if the confidence interval is completely above the goal score.

C.  Near Target. Projected score at goal date: Between (X) and (Y).  This statement appears if the confidence interval includes the goal score, with X and Y indicating the bottom and top of the confidence interval, respectively.

If Statement A appears, the user has a sound basis for deciding that the current intervention is not sufficient and a change to instruction should be made. If Statement B appears, there is an empirical basis for deciding that the goal is not sufficiently challenging and should be increased. If Statement C appears, the student’s progress is not clearly different from the aimline, so there is not a compelling reason to change the intervention or the goal; however, the presentation of the confidence-interval range enables the user to see whether the goal is near the upper limit or lower limit of the range, which would signal that the student’s progress is trending below or above the goal.

A 75% confidence interval was chosen for this application because it balances the costs of the two types of decision errors. Incorrectly deciding that the goal will not be reached (when in truth it will be reached) has a moderate cost: an intervention that is working will be replaced by a different intervention. Incorrectly deciding that the goal may be reached (when in truth it will not be reached) also has a moderate cost: an ineffective intervention will be continued rather than being replaced. Because both kinds of decision errors have costs, it is appropriate to use a modest confidence level.

Calculation of the 75% confidence interval for the score at the goal date

●     Calculate the trend line. This is the ordinary least-squares regression line through the student’s monitoring scores.

●     Calculate the projected score at the goal date. This is the value of the trend line at the goal date.

●     Calculate the standard error of estimate (SEE) of the projected score at the goal date. The means and sums are calculated across all of the completed monitoring administrations up to that date. Add and subtract 1.25 times the SEE to the projected score, and round to the nearest whole numbers.


Evidentiary basis for these rules:

The decision rules are statistically rather than empirically based. The guidance statements that result from applying the 75% confidence interval to the projected score are correct probabilistic statements, under the certain assumptions that: the student’s progress to date can be described by a linear trend line. If the pattern of the student’s monitoring scores is obviously curvilinear, then the projected score based on a linear trend will likely be misleading. We provide training in the aimswebPlus Progress Monitoring Guide about the need for users to take nonlinearity into account when interpreting progress-monitoring data. Another assumption is that the student will continue to progress at the same rate as they have been progressing to that time. This is an unavoidable assumption for a decision system based on extrapolating from past growth.

No controlled experimental study has been conducted to support the decision rules, however, an empirical study of actual progress monitoring results was undertaken to evaluate the accuracy of the decision rules as various points during the progress monitoring schedule. aimswebPlus Number Sense Fluency (NSF) and Oral Reading Fluency (ORF) progress monitoring data collected during the 2016-17 school year was used to evaluate the accuracy of the decision feedback.  All students on a PM schedule who scored below the 30th national percentile on the fall benchmark and who had at least 20 PM administrations were included. Grades 2 and 3 were chosen. More than 1000 student’s scores were used in each grade. Most administrations we collected about weekly.

Because we did not have the student’s actual goal score we generated a goal score based on the ROI that corresponds to a student growth percentile of 55. This level was chosen because it represents an average rate of improvement and it resulted in about 50% of the students meeting the goal. The goal score was computed as follows: Fall Benchmark Score + ROI55*Weeks. Where ROI55 is the ROI associated with the SGP of 55 and Weeks is the number of weeks from the baseline score (Fall Benchmark) and the Spring Benchmark. For each student, beginning with the 8th score and going through the last score, we computed the score feedback based on the rules described in the previous section. If the student was projected to be below target an intervention change was deemed necessary and coded 1.  Otherwise, the student was assigned a score of zero for that administration (no change is needed).

We computed the accuracy of the decision to change interventions by comparing the decision to whether the student ultimately did not meet the goal score by the Spring Benchmark. Accuracy was computed as the percentage of the decisions to change intervention of all students who did not ultimately meet the goal. The results showed that decision accuracy improved with each successive administration with 70% - 75% accuracy by the 8th administration and 75% - 80% by the 15th administration and 90% by the 20th administration. This trend was replicated in each sample and it provides evidence that the decision rules validly indicate when a change in the intervention should be made because the student is unlikely to achieve the goal with the current rate of improvement.

Administration Format

  • Individual
  • Computer-administered
  • Administration Format:



    *Examiner uses digital record form.

    Administration & Scoring Time

  • 1 minute
  • Administration Time:

    1 minute

    Scoring Time:

    Scoring is automatically completed by system when student responses for a given measure are submitted by the examiner.

    Scoring Format

  • Computer-scored
  • Scoring Format:


    ROI & EOY Benchmarks

  • ROI & EOY Benchmarks Available
  • Specify the minimum acceptable rate of growth/improvement:

    aimswebPlus provides student growth percentiles (SGP) by grade and initial performance level (Fall and Winter) for establishing growth standards. An SGP indicates the percentage of students in the national sample whose seasonal (or annual) rate of improvement (ROI) fell at or below a specified ROI. Separate SGP distributions are computed for each of five levels of initial (Fall or Winter) performance.

    Goals are set in the system by selecting the measure and baseline score, the goal date, the monitoring frequency (default is weekly), and the goal score. When the user defines the goal score, the system automatically labels the ambitiousness of the goal. The rate of improvement needed to achieve the goal is computed and translated into an SGP.  An SGP < 50 is considered Insufficient; an SGP between 50 and 85 is considered Closes the Gap; an SGP between 85 and 97 is considered Ambitious; and an SGP > 97 is considered Overly Ambitious. aimswebPlus recommends setting performance goals that represent rates of growth between the 85th and 97th SGP. However, the user ultimately determines what growth rate is appropriate on an individual basis.


    Specify the benchmarks for minimum acceptable end-of-year performance:

    aimswebPlus allows users to select a target from a range of end-of-year targets the one that is most appropriate for their instructional needs.

    aimswebPlus defines a meaningful target as one that is objective, quantifiable, and can be linked to a criterion that has inherent meaning for teachers. To establish a meaningful performance target using aimswebPlus tiers, the account manager (e.g., a school/district administrator) is advised to choose a target that:

    ●     is linked to a criterion,

    ●     is challenging and achievable,

    ●     closes the achievement gap, and

    ●     reflects historical performance results (when available).

    Customers are also advised to give consideration to the availability of resources to achieve the goal.

    The targets are based on spring reading or math composite score national percentiles. Twelve national percentile targets ranging from the 15th through the 70th percentile, in increments of 5 are provided. This range was chosen because it covers the breadth of passing rates on state assessments and the historical range of targets our customers typically use. The system provides a default spring performance target of the 30th national percentile. Targets can be set separately for Reading and Math.

    The aimswebPlus Tiers Guide provides more detail to help customers define a high quality performance target. It also provides a step-by-step method to align spring performance targets to performance levels on state accountability tests.

    Once a target is selected, the aimswebPlus system automatically identifies the fall (or winter) cut score that divides the score distribution into three instructional Tiers. Students above the highest cut score are in Tier 1 and have a high probability (80%–95%) of meeting the performance target; students between the upper and lower cut scores are in Tier 2 and have a moderate probability (40%–70%) of meeting the performance target; and students below the lower cut score are in Tier 3 and have a low probability (10%–40%) of meeting the performance target.

    The system recommends that a progress monitoring schedule be defined for any student below the 25th national percentile in a given season, or in Tiers 2 or 3.