Subject Line AB Test Framework for Cold Email Campaigns

## Overview Generate a structured A/B test plan for cold email subject lines — with test variants, hypotheses, sample size requirements, and measurement criteria for scientific optimization. ## Use Cases - Growth teams building systematic outreach optimization programs with real statistical rigor - Sales ops leaders designing A/B testing protocols for SDR sequence optimization - Outbound agencies proving performance improvements to clients through structured testing ## Why This Prompt Works This prompt is engineered for professional outreach that converts. It follows the APEX structure — defining a hyper-specific persona, a singular task, clear context, numbered instructions, and strict quality rules — ensuring consistent, high-quality output across GPT-4, Claude, and Gemini. ## Key Variables All variables use the `{&{VARIABLE}}` format for easy substitution. Replace each variable with your specific context before using.