PixelPress Pro mobile trial conversion: methods

Generated from pixelpress-trial-conversion.yaml. Status: provisional. Owner: Growth analytics. Updated 2026-10-04.

Question. What share of people who start a PixelPress Pro free trial become paying subscribers?

Definition. Among PixelPress Pro mobile users whose first recorded trial started from 2 through 9 March 2026, 14.3% had a positive charge on days 0-14 after trial start.

Result. Mobile trial conversion rate: 14.3%. 6,894 of 48,210 trial users had a positive charge in the implemented window.

Population

The unit of analysis is the user (One distinct user_id from app.trial_events after taking MIN(trial_start_date) per user for product = 'PIXELPRESS_PRO' and platform IN ('ios', 'android').). Eligibility rules, in the order applied:

Users with at least one PixelPress Pro trial event on iOS or Android. Implementation: app.trial_events rows where product = 'PIXELPRESS_PRO' and platform IN ('ios', 'android'). [S3]
Each user is assigned their first recorded PixelPress Pro mobile trial date. Implementation: The trials CTE groups by user_id and sets trial_start_date to MIN(t.trial_start_date). [S3]
The first recorded trial date is from 2 through 9 March 2026. Implementation: cohort keeps rows where trial_start_date BETWEEN DATE '2026-03-02' AND DATE '2026-03-09', inclusive. (n = 48,210) [S3, S4]

Time zero and windows

Time zero is the first recorded trial start: Each user's clock starts on their first recorded PixelPress Pro mobile trial date. Implementation: trial_start_date is MIN(t.trial_start_date) per user_id from the trials CTE.

Window	Role	Offsets (start inclusive, end exclusive)	Definition
Positive-charge window	outcome	[0, 15) days	b.charge_date BETWEEN c.trial_start_date AND DATE_ADD(c.trial_start_date, p.conversion_days), with conversion_days = 14. Because BETWEEN is inclusive, this is day offsets 0 through 14.

Measures

Had a positive charge (headline) (indicator, charge_days_0_14): Counts a user if they had at least one charge above zero dollars in the window. Implementation: first_charge joins billing.charges where b.user_id = c.user_id, b.amount_usd > 0, and b.charge_date falls in the inclusive charge window, then groups to MIN(b.charge_date). The final summary counts DISTINCT f.user_id.

Aggregation

Divide users with a positive charge by all users in the implemented cohort. ROUND(100.0 * COUNT(DISTINCT f.user_id) / COUNT(DISTINCT c.user_id), 2) AS conversion_rate_pct.

Group	Definition	Value (percent)	n
March 2026 first-trial mobile cohort	product = 'PIXELPRESS_PRO', platform IN ('ios', 'android'), MIN(trial_start_date) BETWEEN DATE '2026-03-02' AND DATE '2026-03-09'.	14.3	48,210

Uncertainty

No confidence interval or standard error was reported for the 14.3% headline. conversion_summary.csv reports trial_users, converted_users, conversion_rate_pct, run_date, and data_complete_through only. Not covered: Random uncertainty, data-quality uncertainty, and uncertainty from the definition discrepancies are not quantified.

Estimand

Attribute	Specification
Population	Users whose earliest recorded PixelPress Pro iOS or Android trial started from 2026-03-02 through 2026-03-09, inclusive.
Exposure	None. This is a single-cohort descriptive rate.
Time zero	Each user's earliest recorded PixelPress Pro mobile trial_start_date.
Variable	Indicator for at least one billing.charges row with amount_usd > 0 and charge_date on day offsets 0 through 14 after time zero.
Intercurrent events	Refunds, internal/test status, and later trial starts are not handled in the saved SQL except that later trial starts do not change time zero.
Summary	Proportion of implemented-cohort users with converted_to_paid = 1, reported as a percent rounded to two decimals.

Limitations

The saved SQL is not a 30-day metric (may make the number look smaller than it really is; high). The README and readout define conversion as payment within 30 days, but the SQL parameter is 14 and the inclusive date comparison counts days 0-14.
The cohort end date differs (could push the number either way; high). The README says the cohort runs through 8 March, while the SQL includes first recorded trial starts through 9 March.
Described exclusions are not visible in SQL (could push the number either way; high). The README says internal, test, and refunded accounts are excluded, but the SQL shown here only requires amount_usd > 0 and does not filter internal users, test users, or refunds.
The February comparison is not reproducible from these files (limits what the number can be used to conclude; medium). The readout quotes a 12.9% February rate and a 1.4-point lift, but the fixture includes no February result, comparison SQL, or uncertainty.
No uncertainty interval saved (the true uncertainty is larger than shown; low). The saved output reports a point estimate only. It does not include a confidence interval, standard error, or sensitivity run.

Description vs implementation

Outcome window length. Described: README and readout define conversion as paying within 30 days of trial start. Implemented: params sets conversion_days = 14, and first_charge keeps charge_date BETWEEN trial_start_date AND DATE_ADD(trial_start_date, 14), inclusive. Impact: A shorter window likely understates the 30-day conversion rate. The size is unknown from the saved files.
Cohort date range. Described: README says trials started 2026-03-02 through 2026-03-08. Implemented: SQL sets cohort_end to DATE '2026-03-09' and uses BETWEEN, so 9 March starts are included. Impact: The implemented denominator can include an extra start date. Direction and size are unknown.
Internal and test account exclusions. Described: README says internal and test accounts are excluded. Implemented: No internal-account or test-account filter appears in the saved SQL. Impact: If such accounts exist in app.trial_events, they remain in the result. Direction and size are unknown.
Refund exclusion. Described: README says refunded charges do not count. Implemented: SQL joins billing.charges with b.amount_usd > 0, but shows no refund, reversal, or net-paid filter. Impact: Refunded positive charges could overstate net-paid conversion. The size is unknown.
First trial versus any trial. Described: Descriptions say users who started a trial in the cohort week. Implemented: SQL first takes MIN(trial_start_date) per user across PixelPress Pro mobile trial events, then filters that first recorded trial into the cohort. Impact: Users with an earlier PixelPress Pro mobile trial and another trial in March are excluded. Direction and size are unknown.
Onboarding lift claim. Described: The readout says the new onboarding is driving a 1.4-point lift and recommends rolling it out to web. Implemented: The saved SQL computes a single March cohort rate only. No February cohort SQL, web cohort, counterfactual, adjustment, or uncertainty is included. Impact: The fixture supports a descriptive March rate, not a causal onboarding claim or web rollout inference.

Reproduction

Run sql/trial_conversion.sql against the app.trial_events and billing.charges tables.
Save the one-row summary to results/conversion_summary.csv.
Recompute converted_users / trial_users * 100 from the saved CSV.
Receipt: conversion_summary.csv reports 48,210 trial users, 6,894 converted users, and 14.30%.
Receipt: Independent arithmetic: 6,894 / 48,210 * 100 = 14.2999%, which rounds to 14.30%.

Completeness. The latest first recorded trial start is 09 Mar 2026; its positive-charge window ends 23 Mar 2026. Data are complete through 17 Apr 2026, so every window is fully observed. This number should not move as more data arrive.

Sources

[S1] eval/fixtures/syn-a/README.md, lines 1-21. Question, prose definition, cohort dates, exclusions, and file list
[S2] eval/fixtures/syn-a/readout.md, lines 1-9. Headline, February comparison, onboarding claim, and 30-day definition
[S3] eval/fixtures/syn-a/sql/trial_conversion.sql, lines 1-43. Implemented cohort, charge window, and aggregation
[S4] eval/fixtures/syn-a/results/conversion_summary.csv, lines 1-2. Saved result row