Everything worth knowing, nothing that isn't.
What you measure
Delivery and failure rates by country and operator (from DLRs), click-through (from tracked short links), reply and opt-out rates, and conversion attributed to the campaign. See /answers/what-is-dlr and /answers/what-is-a-sms-short-link.
Why DLRs are the foundation
With no open rate, operator-level delivery receipts are your ground truth for what arrived and why the rest failed — the basis for improving delivery and cost. See /answers/how-to-improve-sms-delivery-rates.
From metrics to ROI
Combine delivery, click, and conversion data to compute real return, and feed it back into segmentation and timing. See /answers/sms-marketing-roi and /tools/true-cost-calculator.