Person hour
A person-hour , shortly PS , formerly man hours , MS called ( English man-hour, person-hour ) is a unit of time that an exceptionally talented person one hour spends actively working. This term is used to make estimates of the total amount of work required to complete a task. For example, it may take twenty person-hours to write an essay or ten person-hours to prepare a large family dinner.
Applications
Person hours do not include time for breaks, they represent pure working time. If you want to calculate the total time for a task, additional breaks must be taken into account. The above-mentioned essay does not finish in twenty consecutive hours, but is interrupted by other tasks, meals, sleep, and other distractions.
One area of application of person hour calculation is the estimation of team size and total duration of a project. However, you cannot simply divide the number of person hours by the number of team members.
There are many formulas, especially for software systems, that take into account a certain minimum duration of projects and the different degrees of difficulty.
An error in the pure calculation of person-hours arises, for example, from the fact that the organization, training and coordination of additional workers can take up more time than the additional workers save. Furthermore, when estimating the end time of the project, it must be taken into account that often not the entire designated team can work 100% on the project, be it because other higher priority projects are still pending or because part of the team has meanwhile been carrying out maintenance and service tasks is charged.
Person hours are a parameter of scientific management in Taylorism , which was established by Frederick Winslow Taylor , Henry Gantt , Frank Bunker Gilbreth and others.
Other units
Further common units are the person day, the person week and the person month.
- The person day ( PT for short , also "processing day", BT , "man day", MT ) is calculated in Europe as 8 person hours .
- The person week ( PW for short , "man week", MW ) is calculated as five person days.
- The person month ( PM for short , "man month", MM ) is calculated as 20 person days .
Time-works, i.e. daily work (TW), weekly work (WW), etc. are only implicitly personal-related effort descriptions.
Person years
A similar concept, person years ( PJ , also "processing year", BJ or "man year" MJ ), is used for very large projects. It is the amount of work that a person works on average during a year.
- In Germany, 1760 person hours per person year (220 working days times 8 hours without sick days) are often used as the value
This of course depends on the usual working week length and the number of vacation days, which vary greatly from country to country: In 2008, the OECD measured a person-year of 1432 hours for Germany. This is only undercut by the Netherlands with 1389 hours. The maximum in the 24 countries examined is 2120 hours in Greece (for 2007 there is also data for South Korea : 2316 hours). Standard values such as 2000 or 2087 person-hours are given for the USA.
Depending on the hourly wage a person-year corresponds to a value equivalent of less than one thousand dollars ( developing country ) to over 100,000 USD (in the G7 -Staaten).
Individual evidence
- ↑ Barry Boehm: Software Metrics , see also Barry Boehm: Software Engineering Economics. 1981, ISBN 0-13-822122-7 ; Barry Boehm, Chris Abts and A. Winsor Brown: Software Cost Estimation with Cocomo II. Documentation. ISBN 0-13-026692-2 , 2000.
- ↑ This was shown by Frederick P. Brooks in his software engineering book The Mythical Man-Month , German From the myth of the man month .
- ^ OECD Employment Outlook 2009, Tackling The Jobs Crisis . Secretary-General of the Organization For Economic Co-Operation And Development, 2009, ISBN 978-9264067912 , p. 269, (accessed March 30, 2011).
- ↑ Official data up to 2005 in spreadsheet format . Publications on Swivel.com
- ↑ Solicitation Number 05-0002-02: Support Services for the Office of Naval Research for the Legislative Affairs Office ( Memento of the original from July 22, 2006 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . United States Navy Office of Naval Research, Arlington, Virginia, USA, 2004
- ↑ Report 5 . International Federation Of Professional And Technical Engineers Local 32. San Diego, California, 2000. Archived from the original on December 30, 2004 Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (Accessed on March 19, 2006): "counting 311" Non-available / Nonproductive "man-hours"
