Editing Material requirements planning (section)

== History ==
Prior to MRP, and before computers dominated industry, [[Reorder point|reorder point (ROP)]]/reorder-quantity (ROQ) type methods like [[Economic order quantity|EOQ (economic order quantity)]] had been used in manufacturing and inventory management.<ref>Uday Karmarkar, Getting Control of Just-in-Time, Harvard Business Review 1989</ref> MRP was computerized by the aero engine makers Rolls-Royce and General Electric in the early 1950s but not commercialized by them. It was then 'reinvented' to supply the [[Polaris (UK nuclear programme)|Polaris program]] and then, in 1964, as a response to the [[Toyota Production System|Toyota Manufacturing Program]], [[Joseph Orlicky]] developed material requirements planning (MRP).

Early MRP users in the 1960s and 1970s included [[Black & Decker]], [[Twin Disc]], Markem, [[Steelcase]], and American Sterilizer.<ref name="gray19860127">{{Cite magazine |last=Gray |first=Chris |date=1986-01-27 |title=MRP II software |url=https://books.google.com/books?id=33QfOHT69aMC&pg=PA35#v=onepage&q&f=true |access-date=2025-05-29 |magazine=Computerworld |pages=35-48 |volume=XX |issue=4}}</ref> The first company was Black and Decker in 1964, with Dick Alban as project leader. Orlicky's 1975 book ''Material Requirements Planning'' has the subtitle ''The New Way of Life in Production and Inventory Management''.<ref>Joseph Orlicky, Materials Requirement Planning, McGraw-Hill 1975</ref> By 1975, MRP was implemented in 700 companies. This number had grown to about 8,000 by 1981.

In 1983, [[Oliver Wight]] developed MRP into [[manufacturing resource planning]] (MRP II).<ref>WJ Hopp, ML Spearman ''Commissioned Paper To Pull or Not to Pull: What Is the Question?'' Manufacturing & Service Operations Management, 2004</ref>{{r|gray19860127}} In the 1980s, Joe Orlicky's MRP evolved into Oliver Wight's manufacturing resource planning (MRP II) which brings master scheduling, rough-cut capacity planning, [[capacity planning|capacity requirements planning]], S&OP in 1983 and other concepts to classical MRP.<ref>{{Cite web |last=NetSuite.com |date=2020-08-12 |title=ERP: Through the Decades. |url=https://www.netsuite.com/portal/resource/articles/erp/erp-history.shtml |access-date=2023-06-01 |website=Oracle NetSuite |language=en}}</ref> By 1989, about one third of the [[software industry]] was MRP II software sold to American industry ($1.2 billion worth of software).<ref>IE. 1991. Competition in manufacturing leads to MRP II. 23 (July) 10-13.</ref> MRP's appeal is greater financial improvement than other business software. While automating [[payroll]] reduces the need for payroll clerks but requires computer equipment and staff, ''[[Computerworld]]'' said in 1986 that "In companies getting the full benefits of MRP II, however, the [[return on investment]] averages 200%". While accounting software automates manual functions, MRP allows analyses of updated material requirements impossible without computers.{{r|gray19860127}} By then a variety of MRP software was available for [[mainframe]]s and [[minicomputers]], such as ASK's [[Manman (software)|Manman]] and [[IBM]]'s [[MAPICS]].<ref name="zais19860127">{{Cite magazine |last=Zais |first=Adam |date=1986-01-27 |title=IBM reigns in dynamic MRP II marketplace |url=https://books.google.com/books?id=33QfOHT69aMC&pg=PA37#v=onepage&q&f=true |access-date=2025-05-29 |magazine=Computerworld |page=37 |volume=XX |issue=4}}</ref>