Standard celeration chart

Standard geometry makes slopes comparable

The daily per-minute version commonly uses a vertical equal-ratio frequency axis and a horizontal calendar spanning 140 days, or 20 weeks. Major vertical cycles represent tenfold change. Equal horizontal distance represents equal time.

Because the geometry stays fixed, a particular slope carries the same proportional meaning in different locations on the chart. A doubling from 2 to 4 per minute and a doubling from 20 to 40 share the same celeration direction and magnitude.

Changing chart dimensions, axis spacing, or print scaling can defeat that standardization. Verify exports and digital displays rather than assuming the template survived resizing.

Frequency combines count and time

Frequency states responses per unit of time. Ten correct responses in 30 seconds equals 20 per minute when the timing and conversion rule support that calculation. Record the original count and duration so reviewers can reproduce it.

Correct and incorrect frequencies may appear as separate series. Their definitions should be mutually clear, and the chart needs a declared zero convention because zero has no ordinary logarithmic position.

Timing length, available material, prompts, pauses, and opportunity constraints matter. Two one-minute timings are not comparable if one includes setup time or inaccessible communication.

Celeration describes proportional change

Celeration is the multiplication or division of frequency across a time unit. A series that moves from 20 to 40 correct responses per minute over one week has a celeration of ×2 per week. A series that moves from 10 to 5 errors per minute has a divider of ÷2 per week.

A celeration line summarizes the selected observations. State which points, dates, and fitting rule were used. An automated line can be precise while still using the wrong series or period.

A fictional reading-practice example

Omar completes one-minute readings on five school days. Correct frequencies are 18, 22, 25, 29, and 33 per minute. Incorrect frequencies are 5, 4, 4, 3, and 2 per minute.

The chart shows correct responding rising while errors decline. The team records all five one-minute counts, dates, material versions, prompt rules, and Omar’s feedback. One timing occurred after the material changed, so the chart marks that change rather than treating all points as one untouched condition.

The pattern can guide a teaching review. It does not establish that the instructional procedure caused the change, that the skill generalized, or that faster reading is automatically meaningful. Comprehension, comfort, accuracy, choice, and practical use remain separate outcomes.

Chart decisions should be predeclared

A useful chart plan identifies:

• response definitions and units
• timing duration and start-stop rules
• correct, incorrect, prompted, and skipped categories
• zero, missing, and ineligible conventions
• chart type and time base
• condition labels and effective dates
• celeration calculation rule
• decision thresholds and reviewer
• client-accessible outcome checks

Adjust instruction from the full evidence, including client priorities, assent or dissent when applicable, health, context, and implementation quality. A line crossing a criterion does not transfer clinical authority to the chart.

Share the display in a form the learner, family, and relevant team members can understand. Pair chart terms with plain-language counts, examples, and the practical decision under review.

Avoid common reading errors

Equal vertical distances represent equal ratios, not equal additive differences. The value halfway through a visual cycle is not the arithmetic midpoint. Read the labeled logarithmic scale.

A flat line on the SCC represents a stable frequency, while a flat line on a cumulative record means no new responses accumulated. These graphs use slope differently.

Missing data should remain visibly missing. Plotting zero changes the record, and joining across long gaps can conceal interrupted observation.

Audit the chart and its source

Check plotted values against counts and timing durations. Verify axis geometry, dates, condition boundaries, series symbols, zero treatment, celeration inputs, and accessible text or table output.

Chart-source accuracy can be reported as plotted observations matching every required source field divided by observations due for review. Separately report timings missed, invalid, or held. A high match rate says the chart reflects the record; it does not prove the program is effective.

The BACB BCBA Test Content Outline, sixth edition includes measurement, graphing, visual analysis, and data-based decisions. A precision-teaching synthesis describes SCC structure and celeration, and a precision-teaching special section provides contemporary research context. These publications do not impose one chart on every practice.