https://d2cebl.com/studies/ An experiment tests changes side by side, under controlled conditions. A case study shows the results of a business or project, and describes what was done. en-us https://d2cebl.com/studies/rag-optimization-response-time-llm-cost/ https://d2cebl.com/studies/rag-optimization-response-time-llm-cost/ Experiment Average response time fell from 9.1 s to 1.6 s, and LLM cost from $4.03 to $0.46 per 1,000 questions. Answer accuracy barely changed. Fri, 25 Sep 2026 00:00:00 GMT https://d2cebl.com/studies/google-ads-east-coast-moving-company/ https://d2cebl.com/studies/google-ads-east-coast-moving-company/ Case study $1,281,235 ad spend · 64,009 leads · $19.97 cost per lead · 40.04% conversion rate · $9,167,785 in sales · 716% return on ad spend Fri, 25 Sep 2026 00:00:00 GMT https://d2cebl.com/studies/grading-rag-answers-astra-vs-sol/ https://d2cebl.com/studies/grading-rag-answers-astra-vs-sol/ Case study GPT-6 Astra took 44% less time than GPT-5.6 Sol to grade the same RAG answers. They agreed on 95% of verdicts, but Sol graded more strictly. Fri, 25 Sep 2026 00:00:00 GMT https://d2cebl.com/studies/google-ads-tampa-orlando-moving-company/ https://d2cebl.com/studies/google-ads-tampa-orlando-moving-company/ Case study $912,316 ad spend · 37,837 leads · $24.07 cost per lead · 40.88% conversion rate · $6,323,556 in sales · 693% return on ad spend Fri, 25 Sep 2026 00:00:00 GMT