Calculating the Project Duration Using the CPM and PERT Methods

Radi potrebe kontroliranja i nadgledanja velikih projekata s ogromnim brojem aktivnosti, došlo je do potrebe za osmišljavanjem sustava pomoću kojih će se izvoditi takvi projekti. S obzirom na navedenu problematiku, prepoznata je važnost korištenja ovakvih sustava, te su od osnovne metode kritičnog puta i tehnike za procjenu i reviziju programa, nastale brojne izvedene verzije, ovisno o specifikacijama područja u kojem se primjenjuju. Danas se tehnika mrežnog planiranja uspješno se rabi u mnogim područjima poslovanja poduzeća: razvoju, istraživanju, proizvodnji, programiranju, analizi, organizaciji, savjetovanju itd. Svi bitniji projekti planirani su uz pomoć dvije najzastupljenije metode, odnosno CPM i PERT. Osim navedenih, jako zastupljena tehnika je Gantogram, koja služi za jednostavnije projekte. CPM i PERT metode prikazane su u ovom radu, na projektu Foster Children Rights koji se provodi na području Zadarske županije. Glavna bit CPM metode se sastoji u identificiranju kritičnog puta, iz razloga što taj put sadrži informacije o tome koliko je vremena potrebno da se završi projekt. PERT metoda se koristi u slučajevima kada ne možemo sa sigurnošću reći koliko će biti trajanje, odnosno troškovi pojedinih aktivnosti u projektu. Najznačajnija razlika u analizi između metode CPM i PERT je što PERT uzima u obzir nesigurnost u procjeni vremena.For the purpose of controlling and monitoring large projects, of a huge number of activities, there was a need for designing the systems that will help run this projects. Due to mentioned issues, it's recognized the importance of using such systems, therefor from the critical path method and project evaluation and review technique, are created many derived versions, depending on the specifications of the areas in which they are applied. Today, network planning techniques are successfully used in many areas of business: development, research, production, programming, analysis, organization, consulting. All relevant projects were planned with the help of two most represented methods, CPM and PERT. Besides mentioned, very represented method is Gantt chart, which is used for simpler projects. CPM and PERT techniques were also used on this study, on the project Foster Children Rights which is implementing in Zadar County. Gantt chart is also shown in the work. Main essence of the CPM method consists in identifying the critical path, because this path contains information on how long it takes to complete the project. PERT method is used in cases where we can not say with certainty how much will be the length and cost of certain activities in the project. The most significant difference between CPM and PERT methods is that PERT is taking into consideration the insecurity in the estimation of the time