SummaryRELATIVE PREDICTABILITY OF FIVE INDICES OF ADOPTION OF RECOMMENDED FARM PRACTICES: The central concern of this study was to compare five indices of adoption of recommended farm practices in terms of their capacities to predict variations in variables theoretically expected and empirically established to be related to adoption. Of the five indices of adoption, three were conventional indices widely used by rural sociologists in measuring the adoption behaviour of farmers. The first index was comparatively crude ‐ the per cent of applicable practices adopted. The other was an improvement over the first in that the years of use of the adopted applicable practices were taken into consideration. The third index involved a categorization of farmers into five groups in terms of the degree to which each of them was relatively earlier to adopt new ideas than other members of his social system.Besides these three indices, two adoption scales were constructed with the use of trace line analysis and Guttman's scalogram analysis, respectively. The predictive utility of each of these five indices was measured by computing Gutman's coefficient of predictive utility for each of the twenty‐one variables known to be related to measures of adoption.ZusammenfassungDIE BRAUCHBARKEIT VON FÜNF INDIZES FÜR DIE RELATIVE VORAUSSAGE DER ADOPTION EMPFOHLENER L ANDWIRTSC H AFTLIC HERAußer diesen drei Indizes wurden zwei Maßstäbe der Adoption festgelegt, und zwar unter Anwendung dertrace line‐Analyse bzw. des Guttman‐Skalogramms. Die Brauchbarkeit der Voraussage jedes dieser fünf Indizes wurde durch Berechnung des entsprechenden Guttman‐Koeffizienten für jede der 21 Variabelen, die für die Be‐stimmung des Adoptionsgrades beka