How to measure spelling progress with correct letter sequences

Right-or-wrong spelling scores hide growth. A student who moves from "tn" to "tran" to "train" scores zero, zero, then one. Correct letter sequences (CLS) give credit for each part of the word the student got right, so the same student scores 2, then 4, then 6. That makes CLS the better measure for students whose spelling is improving but not yet correct.

This page covers scoring and probing. For spelling goals to measure with it, see spelling IEP goal examples. For teaching that moves the numbers, see spelling interventions for students with IEPs. The pillar guide to IEP goals for writing covers the rest of the writing area.

What you need before you start

• A set of equivalent word lists, one per probe, drawn from the patterns the goal targets (or from grade-level lists for a general spelling measure).
• A timer and a fixed dictation pace, such as one word every 7 or 10 seconds.
• Lined paper with numbered lines.
• A scoring key with each word's possible sequences written above it.
• The goal, with the rate written in it, such as "at least 24 correct letter sequences per minute."

Step 1: Learn the counting rule

Put an imaginary space before and after the word. Every adjacent pair, including those two spaces, is one possible sequence. So the number of possible sequences is the number of letters plus 1.

"Cat" has 4: space-c, c-a, a-t, t-space. "Jumped" has 7. Count a sequence as correct when the two letters (or the letter and the space) appear next to each other in the right order in the student's spelling, matching the correct spelling.

Correct letter sequences are a standard curriculum-based measurement score for spelling. The IRIS Center's module on classroom assessment explains how CBM probes like this give a quick, repeatable measure of growth.^[1]

Step 2: Score a few words by hand

Practice on real errors before scoring a probe. Here are six words from a third grader's dictation:

Six words, 36 possible sequences, 22 correct. A right-or-wrong score for the same list is 1 of 6. The CLS score shows a student who hears most sounds and knows many patterns but has gaps with vowel teams, doubling and irregular words. That is far more useful for planning than "17%."

Step 3: Give the probe the same way every time

Standardize everything:

1. Say the word, use it in a short sentence, and say the word again.
2. Give the next word on a fixed pace, such as every 7 seconds for taught-pattern lists or every 10 seconds for younger students.
3. Stop at the time limit, usually 2 minutes.
4. Do not repeat a word on request, and do not tell the student whether a spelling is right.

A 2-minute probe at one word every 7 seconds gives about 17 words. Use a different list of equivalent words each week so the student cannot memorize the probe.

Step 4: Total the sequences and find the rate

Add the correct sequences across all words written. Divide by the number of minutes to get correct letter sequences per minute. A student who earns 48 CLS on a 2-minute probe has a rate of 24 per minute.

If a goal uses accuracy instead of rate, divide correct sequences by possible sequences for the words given. Pick one and keep it. Rate captures speed and accuracy together; percent CLS captures only accuracy.

Step 5: Take a baseline and set the goal

Give three probes on different days and take the median. Set the target from that baseline and the growth you expect over the IEP year, not from a round number. The baseline data guide explains the median and range in more detail.

Step 6: Probe weekly and graph

Probe once a week and plot each rate on a graph with a goal line from the baseline to the target. Progress monitoring works because short, repeated measures under the same conditions show a trend early.^[2] After 6 to 8 points, compare the trend with the goal line and decide whether to keep going or change instruction.

Worked example: Lena's taught-pattern dictation

Lena is a fictional third grader in a structured spelling program. Her goal follows the timed dictation template: given a 2-minute dictation of words from patterns taught so far, one word every 7 seconds, she will write each word before the next one at a rate of at least 24 correct letter sequences per minute, in 3 of 4 consecutive weekly probes.

Her three September probes earn 26, 30 and 28 CLS in 2 minutes. The median is 28, so her baseline is 14 CLS per minute. She also scores 3, 4 and 3 words fully correct out of 17, which would have looked like no progress at all for several weeks.

Over 8 weeks Lena's rate rose from 14 to 20 CLS per minute, about 0.75 per week. At that pace she would reach about 24 by week 13 or 14, ahead of the annual review, so the team keeps the plan. Her words fully correct moved from 3 to 8, but slowly and unevenly. The CLS graph showed the trend weeks earlier.

Common mistakes and better versions

Weak: Forgetting the boundary spaces, so "cat" has 2 sequences instead of 4.

Better: Write the possible count above each word on the scoring key, letters plus 1, and score against it.

Weak: Probing with the week's practiced spelling list.

Better: Use unpracticed words from taught patterns, or a fixed pool of grade-level words, with a new list each week.

Weak: Letting the student finish words after time is called, or repeating words on request.

Better: Fixed pace and fixed time. What is on the page at the bell is the score.

Weak: Reporting raw CLS from a 2-minute probe one week and a 3-minute probe the next.

Better: Convert to CLS per minute, or keep the probe length identical all year.

Weak: Counting letter reversals or poor formation as errors.

Better: Score the letter the student meant if it is identifiable, and track handwriting separately. A common convention is to score a reversed b or d as correct when the intent is clear; state the convention you use on the data sheet.

Weak: Using CLS for a student who already spells most words correctly.

Better: Switch to percent of words correct in the student's own writing. CLS helps most when spellings are partly right.

Goals and tools that use correct letter sequences

• Increase correct letter sequences on timed spelling probes uses grade-level words at one every 10 seconds.
• Write dictated sentences on a timed probe scores sentence dictation, which shows whether spelling holds up with more to remember.
• Write content vocabulary on a timed dictation suits middle school students with science and social studies terms.
• The spelling goal bank has every spelling template with its measure.
• Rate per minute explains how timed rates work across skills.
• Paste a draft goal into the goal checker to catch a missing time limit or pace.

The What Works Clearinghouse elementary writing guide lists spelling among the skills students should be taught to use fluently.^[3] A timed CLS probe measures exactly that combination of accuracy and speed.

Frequently asked questions

Use it in IEP Atlas

• Spelling goals (writing)
• Correct letter sequences in the IEP glossary
• Curriculum-based measurement in the IEP glossary
• Rate per minute measurement guide
• IEP goal checker

Related guides

• IEP goals for writing: written expression, spelling and mechanics
• Spelling IEP goal examples, including goals for students with dyslexia
• Spelling interventions for students with IEPs
• How to measure writing: total words written and correct word sequences

Sources

1. Classroom Assessment (Part 1): An Introduction to Monitoring Academic Achievement in the Classroom, IRIS Center, Vanderbilt University
2. Progress Monitoring: Data & Goal Setting, National Center on Intensive Intervention
3. Teaching Elementary School Students to Be Effective Writers, What Works Clearinghouse, Institute of Education Sciences

Written and checked by the IEP Atlas editorial team under our editorial policy. This guide describes general practice and federal rules. It is not legal advice; your state may add requirements, and the IEP team makes the decisions for each student.