Chapter II STANDARD COUPLE-YEARS OF PROTECTION

It is now generally accepted that evaluation of national family planning programmes must be directed to determining achievements and assessing strategies on a number of levels, including the administrative, demographic, financial and political levels. Furthermore, the results of these assessments must be represented in a convenient form for annual or other appropriate periods. What a family planning programme accomplishes may be measured in many ways. For example, programme achievements may be represented by a mass of statistics on such topics as acceptors by age, parity and method; continuation rates, pregnancy rates, conversions between methods and so on. But in such cases, the larger the number of different indices displayed, the more hopeless becomes the task of drawing comparisons between years or between programmes. 1 It was to overcome this problem of interpreting achievements from service statistics and clinical records that Wishik? introduced the concept of combining the incidence of long-term contraceptive methods with the prevalence of short-term methods into a single index known as couple-years of protection (CYP). This index summarizes the total achievement of a year's programme work into a single figure, satisfying at least some of the needs which demand such an assessment. For the most important tasks, however, it has very serious deficiencies. 3 It cannot be used to compare successive years or different areas in terms of the impact of the programme on fertility. This limitation exists because, in terms of birthpreventing effect, the couple-years of protection summed to yield the accomplishment index are a mixture of many different values, specifically: