9%
of shoppers who meet an empty shelf buy nothing at all. Another 31% buy it in a different store.
Gruen, Corsten & Bharadwaj, Retail Out-of-Stocks: A Worldwide Examination, GMA, FMI and CIES, 2002. 71,000 shoppers in 29 countries.
What the research says about the shelf
Thirty years of studies agree: what happens at the shelf moves sales. Every number links to its source.
Headline findings
4%
of sales lost by a typical retailer to out-of-stocks.
Gruen, Corsten & Bharadwaj, 2002.
+28%
more shoppers notice a brand when its facings go from four to eight.
Chandon et al., Does in-store marketing work?, Journal of Marketing, 2009. Eye-tracking study.
0.17
average shelf space elasticity: 10% more space, about 1.7% more sales.
Eisend, Shelf space elasticity: a meta-analysis, Journal of Retailing, 2014. 1,268 estimates.
80%
of launches barely change their sales rank after week 8. The first weeks set the course.
NielsenIQ, The CPG innovator’s guide to vitality, 2023.
The studies, by question
Do empty shelves cost sales?
Yes, and the problem has proved stubborn.
8.3%
Average out-of-stock rate worldwide. 70 to 75% of out-of-stocks start in the store, not the supply chain.
Gruen, Corsten & Bharadwaj, GMA, FMI and CIES, 2002.
No better
Out-of-stock rates had not fallen over the previous decade, and shoppers were switching stores more often.
Corsten & Gruen, International Journal of Retail & Distribution Management, 2003.
Both lose
Stock-outs cause real losses for manufacturers and retailers alike; how much depends on the product and the shopper.
Campo, Gijsbrechts & Nisol, Journal of Retailing, 2000.
40 years
A review of four decades of out-of-stock research, titled for its conclusion: the shelves are still empty.
Aastrup & Kotzab, International Review of Retail, Distribution and Consumer Research, 2010.
Do space and position move sales?
Position matters most. Extra facings help, with diminishing returns.
+4%
Sales and profit from store-specific shelf sets in field experiments. Shelf location had a large effect; extra facings much less, once out-of-stocks were avoided.
Drèze, Hoch & Purk, Journal of Retailing, 1994.
0.17
Average shelf space elasticity, lowest for staples and highest for impulse products. Adding space does more than removing it costs.
Eisend, Journal of Retailing, 2014.
Do shoppers see what is there?
Only part of it. Facings and position decide what gets noticed.
60% → 76%
Shoppers noticing a brand as its facings double from four to eight. Twelve facings add only 7% more.
Chandon, Hutchinson, Bradlow & Young, Journal of Marketing, 2009 (working paper figures).
80%
Of innovations don’t move their sales rank by more than 20% between week 8 and week 52.
NielsenIQ, 2023.
Do stores follow the plan, and what does it cost?
Often not, and the bill runs to billions.
75% vs 83%
Drugstore planogram adherence for manufacturers not winning their category, against those that were.
GMA & McKinsey, Customer and Channel Management Survey, 2012. Manufacturers’ own averages.
6.4%
Of gross sales reported lost each year to in-store inefficiencies, in a survey of 200 U.S. retail executives.
Coresight Research, sponsored by Simbe and RELEX, 2026.
~70%
How often the average store follows its planogram, in a trade estimate cited by academic work on compliance checking.
Shapiro, 2009, as cited by Yücel & Ünsalan, 2022. A trade figure, not a measured study.
Can software read a shelf reliably?
Dense shelves are hard, and now well studied.
147
Products in an average shelf photo, across 11,762 images. The benchmark that made dense shelves a research problem.
Goldman et al., SKU-110K, CVPR 2019.
7,000+
Stores running camera-based planogram checks, with 99.86% product classification accuracy reported.
Ou, Ponce, Lee & Wu, 7-Eleven Taiwan, 2025. Preprint.
0.97
F1 score for automated planogram compliance checks on a supermarket dataset.
Yücel & Ünsalan, 2022. Not peer reviewed.
Most of this research is from grocery and general retail, few studies are pharmacy-specific, and none of it measures Pharos. A pilot measures your shelves.
See it on your own shelves
One category, a group of your stores, measures agreed up front.