Having five separate cards causes the reader to take more time in handling cards in order that he may save mental effort and avoid error in interpreting the yearly waves. Having five years on one card saves handling the cards, but it takes more mental effort to be accurate in reading the curve horizontally. The choice between five cards of one fiscal year each and one card for five years must rest with the judgment or the habit of mind of each individual person.

It sometimes happens that the seasonal wave in a curve is almost completely obscured by the tendency toward a very great increase or decrease in the business. Conditions may give so large an increase in volume of business in any one year as to more than offset any de-

282 GRAPHIC METHODS

crease due to a seasonal period of slackness. The manager may think, therefore, that his business is not affected by seasons, when in reaHty the seasonal changes are very great. The extent of these might be very evident if, for instance, a panic year should come along and suddenly stop the upward tendencies in the curve resulting from the rapid increase in the size of the business. This is an important point for any small business to watch, for it may involve bankruptcy to assume that the particular business is not affected by slack seasons of the year such as affect most businesses. Fig. 211 gives an example of a curve in which a large amount of seasonal fluctuation might be easily seen if the rapid increase in the business did not make the upward trend from increased sales greater than the possible downward trend due to seasonal changes.