Anyone used segmentation to figure out why a product is losing shelf space?

Segmentation is exactly the right angle here — specifically a switcher analysis where you isolate buyers who used to purchase the national brand but shifted to store brand in the last 6-12 months. Run a quick survey with attitudinal and behavioral variables, then cross-tab against purchase drivers to see if it's pure price sensitivity or something like perceived quality parity. Tools like Qualtrics + a panel (Lucid works fine for CPG) can get you fieldwork done in under two weeks.