Hi Mark!! Yeah there's studies out there, and they're done by the companies who make the equipment to overcome the inadequacies and frailties of the human inspector. Not to say that these studies are not valid, but one just has to keep in mind that these studies MAY have a possible slant to justify their equipment. With that in mind, there's a good spreadsheet that Teradyne has put out that shows defect rates and missed oportunities using visual inspection/ICT vs. AOI. It's at: http://www.teradyne.com/prods/cbt/products/aoi/optima_anim/downloads/3_2sectio n.xls (Type all the letters in with no spaces) For the ergonomic side of things, go to: http://www.visioneng.com/casestudies/health_and_safety.htm It's at Vision Engineering's web site and the link has a *.PDF file of a study that was done at medical screening laboratories and the problems that people have where medical slides are inspected under magnification on a daily basis. It's a pretty good article... -Steve Gregory- > Does anyone out there have a lead to any specific research or studies on > the effectiveness of manual inspection of PCBA's? A crude rule-of-thumb > that we've often used is 80% (80% of actual defects are found by a single > inspection). I know there's a ton of variables (PCBA complexity, component > technology, magnification, fatigue, etc...) but I would think someone would > have documented a thorough study sometime. We've got a customer that's > demanding justification for our rule-of-thumb. > > Also, can someone recommend a good ergonomics reference regarding manual > inspection? Thanks in advance. >