Decide what would interrupt an A/B test before the first visitor arrives.

A fictional studio compares two consultation buttons. Halfway through the planned window, its form starts failing on mobile. A higher completion rate on one button is now only part of the story.

Write the interruption rules alongside the experiment plan: • Define the eligible audience, assignment method and exclusions before the run • Use one reporting timezone and a planned start and end • Name the functional failures or data-quality issues that require an early stop • If a guardrail is breached, record when it happened, which observations may be affected and who owns the investigation • Keep the original plan and source exports with the deviation record so the next reviewer can understand what changed

Choose the next step after reviewing the issue and the evidence. Reaching a minimum count does not resolve a broken form or make an interrupted run a reliable winner.

The preview is the actual Predeclare the plan worksheet from the Business Experiment and A/B Results Kit. The download includes an editable Word packet, Excel tracker, printable PDFs, a fictional completed example and Quick Start.

The kit documents a manual comparison. It does not assign website traffic, detect failures or perform a statistical significance test.

Explore the kit: https://contra.com/products/DT2ZXGKY-business-experiment-and-ab-results-kit

When batch sizes differ, calculate the overall minutes per unit from totals.

A fictional print-studio example: • Batch A takes 50 elapsed minutes for 10 completed orders: 5 minutes per order • Batch B takes 40 elapsed minutes for 20 completed orders: 2 minutes per order

Across both batches, that is 90 minutes for 30 orders, or 3 minutes per order. Averaging the two row rates gives 3.5, because it gives each batch equal weight despite the different order counts.

Before combining observations: • Keep the same start and finish boundary and definition of a completed unit • Check order mix, interruptions and other conditions; split unlike work into separate comparisons • Add elapsed minutes and completed units, then divide the totals • Retain the individual records so variation remains visible

The preview shows the actual Calculate and compare worksheet from the Process Time Study and Bottleneck Review Kit. Its Excel tracker uses total elapsed minutes divided by total units for the overall rate. The download also includes an editable Word packet, printable PDFs, a fictional completed example and Quick Start.

These are observed sample averages. They do not establish a standard labor rate, staffing requirement or employee performance rating.

Explore the kit: https://contra.com/products/nOreSjym-process-time-study-and-bottleneck-review-kit