wTime is a difficult thing to measure. Time is something we cannot manipulate. We have no way of ordering a longer or shorter day. (If we could, most of us would order very long vacation days!) And although time runs the same around the world, human societies have come up with very different ways of measuring increments of days.

It is a conceit of Western civilization that it has the best method for keeping track of weeks, months, and years. But all advanced cultures have developed calendars, and each calendar serves the needs of its culture.

There is nothing intrinsically right about a 365-day year that's divided into 12 months of varying lengths. It is more correct to say that the Western calendar--which is known as the Gregorian calendar--adequately serves the needs of Western civilization.

The Earth takes about 365 and 1/4 days to orbit the sun. Calendars based on the Earth's orbit are called solar calendars, since they approximate the length of one solar year. And every four years, the four quarter-days produce February 29--the leap year phenomenon.

Other cultures, including several in Asia, make use of a lunar calendar, which is divided into months suggested by the interval between new moons (about 29-1/2 days). Both Judaism and Islam use lunar calendars. In Judaism, years come in varying lengths, ranging from 353 to 385 days over a 19-year cycle. A Muslim year, in contrast, is 354 or 355 days long.

Because different calendars do not remain in synch with each other, it's vital that Western executives doing business with Israel or Saudi Arabia, for example, keep track of the local calendars. An Islamic holiday that occurs in March one year might occur in February the next year.

Similarly, differing concepts of months can also cause confusion. A Western business executive who promises delivery within one month may be assuming a period of 31 days. In contrast, a person in a culture which uses a lunar calendar will expect delivery within 29 days.

And while many societies define a week as seven days, different cultures designate different days as periods of rest. And usually, this is based on religious tradition. In most of Europe and the Americas Christianity designated Sunday as the day of worship and rest. For this reason the workweek runs from Monday through Friday (or Saturday). But in Judaism, Saturday is the Sabbath (specifically, sundown Friday through sundown Saturday). So in Israel, Sunday is the start of the workweek--and most people take Friday and Saturday off. In Islamic countries, people attend mosques on Friday, and the workweek usually starts on Saturday.

What year is it? The answer is not as straightforward as you might think. In the Gregorian calendar the current year is AD. 1997. And while the fast-approaching millennium year of 2000 is a big deal for many Westerners, much of the world is indifferent to this milestone. Both the Jewish and Chinese calendars passed the year 2000 mark long ago. In the Jewish calendar, this is the year 5758; in the Chinese calendar, this is the year 4695.

So if you feel threatened by the millennium, remember that time is relative and dates are arbitrary. Consider other calendars, and try to take the long view.

Reprinted from IndustryWeek, October 28, 1997