Subject line experiment: study protocol

Define the decision

This page is a proposed research protocol, not a completed study or a report of findings. The decision is: Does one truthful subject produce a better downstream response for an otherwise identical message? The observation unit is one prospect assigned one subject. Define the population and owner before collecting records; do not substitute an available convenience dataset without documenting the change.

Work through the procedure

1. Record exact subject strings, body version, mailbox and segment. Choose qualified replies as the primary outcome rather than tracked opens.
2. Balance assignments within mailbox and segment. Do not use fake reply prefixes or urgency as a test treatment.
3. Before collection, write the primary outcome, observation window, exclusion rules and stopping conditions. Preserve excluded observations with a reason rather than quietly removing them.
4. Pilot the procedure with fictional or owned test data, resolve ambiguous fields, and freeze a dated protocol version before the main run.

Worked example

The following is a synthetic example for this procedure, not a customer result or performance benchmark.

A: reporting handoff; B: question about reporting handoff; unchanged body and observation window
Suggested record fields: observation_id, condition, evidence_reference, outcome, exclusion_reason, reviewer, protocol_version
Status: illustrative record only; no study has been run for this page.

Read the result

Analyze unique prospect replies with uncertainty. A difference in image requests cannot establish a difference in human reading. Keep the numerator, denominator and missing evidence visible. If the available observations cannot answer the registered question, report that limitation rather than selecting a more favorable metric after collection.

Collect the evidence

Observation unit: prospect.

Eligible contacts and two exact truthful subjects with a fixed body.

Balance mailbox and segment; do not use opens as the primary human-engagement outcome.

Analysis: Qualified replies per assigned prospect; no winner from tracking pixels alone.

Download the JSON collection template under Source references. Set an owner, eligibility rules, outcome definition, observation window and sample justification before collecting records. Templates contain no participant data or results; keep original private records outside the public website.

Check before moving on

1. Name the person responsible for collection and review.
2. Check that the evidence can be inspected without exposing private messages or credentials.
3. Record deviations from the protocol and analyze their possible effect.
4. Retain a dated, redacted evidence worksheet with the final interpretation.

Limits and next action

Repeated tests across many subjects increase false discovery risk. Register one primary comparison and disclose exploratory follow-ups. Publish results only after the evidence, method and limitations have been reviewed. This protocol provides no benchmark, expected lift or completed-study claim.

Source: Method or workflow reference