Answer
How long should you run an AI automation alongside the manual process?
One full cycle of whatever the process is, with the disagreements recorded. Then stop, because an open-ended parallel period never ends.
One complete cycle of the process, with every disagreement between the two recorded. Set the end date before starting, because a parallel period without one continues until somebody notices the business is running two systems.
The purpose of parallel running is to generate evidence, and evidence has a required quantity rather than a required duration. What you need is enough cases to see the automation handle the variety the process actually contains: the end of month, the awkward customer, the item that arrives in the wrong format, the week when volume doubles. That is one full cycle for most processes, and the cycle length is a property of the business rather than a general rule.
The evidence only exists if disagreements are recorded. Running both and looking at the outputs produces an impression; recording every case where the two differed, and which was right, produces a rate and a list of failure types. That list is what tells you whether to proceed, and it is also the specification for the fixes. Parallel running without this is a delay rather than a test.
Setting the end date at the start is the part that determines whether this works. An open-ended period has no natural conclusion, the manual process continues at reduced volume, and the business quietly acquires a permanent duplicate. Nobody decides this; it is what happens when nobody decides. Naming the date and the criterion — we stop when the disagreement rate is below this, or on this date, whichever comes first — makes the conclusion a decision.
There is a cost to running in parallel that argues against extending it, beyond the obvious duplication. People operating both paths pay attention to neither properly, and the manual process performed as a check is performed less carefully than the manual process performed as the job. So the comparison degrades over time, and a long parallel period produces worse evidence than a short one, not better.
What to do at the end depends on the recorded rate rather than on confidence. If the disagreements are few and their types are understood, switch and keep a sample check. If they cluster in a recognisable category, fix that category and run a shorter second period on it specifically. If they are numerous and varied, the automation is not ready and extending the parallel period will not change that, since the problem is the design rather than the tuning.
One thing to preserve after switching: the manual procedure, written down. Parallel running is the last moment at which the manual process is being performed by people who remember it, and capturing the steps then costs almost nothing. Doing it later means reconstructing it, and doing it during an outage means not having it.
Parallel running without an end date is not caution, it is two processes and a decision nobody made.
Siddharth Sharma, Context Theory
Related questions
Should the automation act during the parallel period, or only produce output for comparison?
Comparison only, in most cases. Both acting means reconciling two sets of changes, which creates work and risk without adding evidence, since the comparison of outputs is what you actually need. The exception is anything where acting reveals a failure mode that producing output does not, such as a workflow whose behaviour depends on the state it creates.
Who should do the comparison?
The person who owns the process, on a sample rather than exhaustively. Comparing everything is a substantial job and a sample gives the same rate. What matters more than volume is that the comparer is someone who can tell which output was right, which excludes whoever built the automation and anyone unfamiliar with the process.
METHOD
Every figure below carries its source and the date it was verified. Nothing on this page is asserted.
The numbers on this page.
| What | Value | Specific to |
|---|---|---|
| Sub-15-minute compliance — automated routing vs manual only | 62.5% vs 39.1% | Category-wide |
| Close rate — response under 5 minutes vs over 24 hours | 32% vs 12% | Category-wide |
2026 speed-to-lead benchmark · verified
Optifai speed-to-lead benchmark · n=939 companies · Q2 2025–Q1 2026 · verified
What is specific to this page.
| Kind | Claim | Check it against |
|---|---|---|
| Workflow | The requirement for parallel running is coverage of the variety the process contains — period ends, awkward cases, format anomalies, volume peaks — rather than a duration, and that coverage corresponds to one full cycle whose length is a property of the business. | Listing the situations the process encounters in a cycle and checking which occurred during the parallel period. |
| Response | Recording each disagreement and which side was right converts parallel running from a delay into a test, producing both a rate and a list of failure types that specifies the fixes. | Checking whether disagreements during a parallel period were recorded or only observed. |
| Constraint | A manual process performed as a check receives less attention than one performed as the job, so comparison quality degrades over time and a longer parallel period produces worse evidence rather than better. | Comparing the disagreement detection rate in the first and last weeks of a long parallel period. |
| Procurement | Parallel running is the last point at which the manual procedure is performed by people who remember it, so capturing the written steps then is nearly free while reconstructing them later is not. | Attempting to write the manual procedure for a process automated more than a year ago. |
Each row would be wrong on another industry's page. Where a sourced figure exists it is in the table above instead; these are the constraints that shape the work and do not happen to be numbers.
Start with the measurement.
Reading about a benchmark is not the same as knowing your own number. The audit produces yours, measured rather than estimated.
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