This question covers a broad scope of considerations so an in-depth answer on each point isn't possible. Loss prevention has been a focus or concern from an ongoing historical point of view. It is more recently that security has been incorporated with loss prevention in companies--this is especially true in retail--to reduce and limit what is now referred to inventory shrinkage, which comprise three categories of product loss: employee theft, vendor theft, and customer shoplifting.
Loss prevention is implemented through an on-site physical presence who mingles with the customers to visually evaluate the third category of inventory shrinkage: customer shoplifting. Loss prevention personnel are authorized to apprehend those caught in the act of shoplifting or attempting to shoplift. Statistically, the success of loss prevention is low with many violators being overlooked or ignored as customer service personnel may have the wrong impression about the significance and importance of apprehending violators witnessed in the act of shoplifting.
Security is a physical presence or technology or persons that give psychological or human physical deterrence to the intention of or attempt at theft or shoplifting. One area in which security is exceptionally useful is that of employee and vendor theft. If technology is used, the knowledge of surveillance records of employee or vendor actions have proven a significant deterrent. If physical human contacts are used, and, for example, searches made, this has equally proven to be a significant deterrent to theft. in addition, the human physical presence of a guard at the customer entrances and exits has also proven significant.
Research into the optimum combinations and the varying situational needs for the newly emphasized security aspect of inventory shrinkage control include such things as research on utilization of video surveillance, physical security personnel presence, best practice involvement of customer service employees and many other areas. This research can be incorporated into employee and security personnel training as the rationale and intended choices behind management selections are explained and as instruction in procedure and policy protocol is given. Education and training on all these aspects (the whys, hows, whats of security and loss prevention to control inventory shrinkage) provides a significant increase in inventory retention and is proving to be of growing importance.