Quarterly figures may be required when only a sequence of yearly totals is available. This article discusses some reasonable procedures to "interpolate" these quarterly figures.I. THE PROBLEM THE problem of deriving quarterly figures, given annual totals only, has been discussed by Lisman and Sandee (1964). A problem of this nature may very well arise if, in a multiple-regression analysis, quarterly data are available for all but one of the explanatory variables, for which only one yearly figure is available. Apart from the drastic but highly unsatisfactory procedure of simply deleting this variable, one can then proceed either by aggregating all other variables to yearly totals (at a loss of 75% of the observations) or by "reasonably" deriving the quarterly values from the annual totals. This is what Lisman and Sandee did. Their criteria for reasonableness were:(i) The sum of the quarterly figures should, for each year, equal the given yearly total.(ii) Symmetry considerations, in particular the requirement that if the yearly totals in three successive years are t 1 , t 2 and t 3 , the quarterly figures for year 2 are the same but in reverse order from what they would have been had the yearly totals been t 3 , t 2 , t 1 (that is, had the yearly totals been in reverse order).(iii) Trend considerations, in particular the desire that if the yearly totals in three successive years rise by equal steps (t 2 -t1 = t3 -t 2), the quarterly figures duringyear 2 should also rise by equal steps (of length n(t 2 -t1»'(iv) Cycle considerations, in particular the requirement that t 2 -t 1 = t 2 -t3 (for example, a sequence 80, 100, 80), the quarterly figures during year 2 should lie on a sinusoid.Lisman and Sandee (l964) showed that these four requirements-recorded here in what is felt to be decreasing order of reasonableness or increasing order of arbitrariness-lead uniquely to the result [ x s ] [0'073 0·198 -0'021] [t] X6 -0,010 0·302 -0,042 1 X7 = -0,042 0·302 -0,010 .~2 , X 8