Dear friends,
As far as I know these terms are used as follows -
1. Man days lost -
This term used mainly in industrial sector for the "stoppage of normal work" either due to -
i. Strikes, lockouts, lay off, hartal, bandhs, sit-in-dharna, gate meetings, accidents etc. - these are mostly collective action by the workers. This is to ascertain basically to sum up the loss of production or services, delays to refix the targets/dates etc. And in most incidents " no work no pay" formula. Govts. require data to give reports on loss due to these unforeseen/foreseen stoppages to the companies, govts. etc. Sometimes in prolonged stoppage like strikes there arises a dispute reg. continuity of service etc.
Calculation = 1000 workers stopped work on 26.12.11 in all the three shifts means 1000 x 3 x 3 = 9000 (9000 shifts) man days lost. Similarly part of the shifts also could be stated. While it is converted into money and related to cost, if it is paid, cost escalates > profit reduces. Supposing "No work No Pay" cost marginally escalates in the form of "fixed over heads" but targets slips.
2. Restricted workday case ?
This is also similar term but mostly used for other reasons - for e.g. There were local festivals which require closure of works few hours early of normal duty hours say for "half a day" or disperse two or 3 hours early. Or in house functions like Ayutha pooja. In some instances of eclipses works either open few hours late or closes few hours early. On these days the main difference is these days neither declared holiday nor a full working day but full wages are paid. Due to short of working hours definitely there will have to be shortage in full production in a shift. Sometimes on sudden riots for e.g. death of a popular leader in India violence break out instantaneously and estts. are forced to evacuate the workers immediately fearing danger to the lives of their workers (schools for e.g.). On such occasions there won't be salary cut.
With reg. to Accidents in work places, Man days are lost, the IR dept. collects such statistics on daily basis to report to the Inspector of Factories/Directorate of Mines in their periodical report under these various reasons. Factories are legally bound to furnish such information, failure to do so is punishable with fines as well.
Am I correct dear ?
kumar.s.