The hypothesis: free shipping threshold lifts AOV (orders near $45 get pushed to $50+) and may lift conversion (removes shipping-cost friction at checkout).

The economics:

Per-order delta:

Gain: shipping-incentivized users spend $5-15 more per order, lifting gross profit.
Loss: shipping cost shifts from customer ($7) to business (say, $4-5 actual cost). Company absorbs ~$4-5 per free-shipping order.
Net per order: depends on how much AOV lifts and what fraction of orders cross the threshold.

For this to break even: AOV lift × gross margin > shipping absorption cost.

The analysis approach:

Baseline distribution. What's the current order distribution? If median order is $30, a $50 threshold is aggressive — few orders naturally cross it. If median is $55, most orders already clear.
Elasticity estimate. How many marginal orders will be pushed from below to above the threshold? Look at current order-size distribution at $35-$50 — those are candidates for push-up.
A/B test. Pilot in one geo or one user segment:
- Treatment: $50 free shipping threshold.
- Control: $7 flat shipping.
- Measure: AOV, conversion rate, gross margin per order, return rate, total revenue per session.
Decision rule: ship if gross profit per session ≥ current. Null or drop: kill.

Second-order effects:

Returns. Free-shipping psychology tends to increase returns — 'no cost to ship it back, let me try it.' Track return rate specifically.
Gaming. Users start adding filler items to hit $50, then returning the filler. Catch via return rates on specific SKUs.
Anchoring. Once users expect free shipping, rolling back is painful. This is a ratchet decision.
Competitive pressure. If all your competitors have free shipping and you don't, pricing isn't the main question — share loss is.

Threshold choice:

Should the free shipping threshold be $50, $35, $75? Every dollar up trades AOV lift for shipping-cost exposure. Use the order distribution:

$75 threshold: few orders cross, high AOV lift per crossing, low shipping exposure. Small gain, small risk.
$35 threshold: most orders cross, minimal AOV lift, high shipping exposure. Probably net-negative.
$50 tends to be optimal when median AOV is $35-45 — enough of a push to work, not so low that it just absorbs cost without lift.

Stakeholder framing:

"Break-even depends on AOV lift vs. absorbed shipping cost. My best estimate: at current order distribution, a $50 threshold should be net-positive on gross profit per session, roughly +2-3%. Let's A/B test in one region for 30 days before rolling broadly."

What senior candidates add:

The behavioral-economics angle: free shipping has stronger psychological pull than a matching discount. Users prefer free shipping over a $5 discount on a $50 order, even when mathematically identical.
Amazon's Prime is the extreme version — bundling free shipping into subscription. Worth mentioning as a strategic context.

Should an e-commerce site offer free shipping above $50?

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