Determinación de la confiabilidad del instrumento de efectividad familiar

astudy was carried out with the purpose of determining the reiability ofthe spanish version ofthe assessment scale of family functionality familiar, by marie luise friedemann, and to identify the effectiveness of family functionality through the application ofthe instrument in 883 families in the city ofvillavicencio. methodology included a descriptive design with quantitative approach, cross-cutting. reliability was assessed through the alpha reliability method by cronbach, with every item. results show that the instrument's intra-individual coefficients are between 0,691 and 0,742; there was internal consistency among items. in family functionality effectiveness, classification of families' dimensions and goals was in levels low and mid, with the following percentages: coherence, 46%; individualization, 47,5%; maintenance, 29%; system change, 52%. goals: growth, 49%; control, 52% and spirituality, 47%. in conclusion, 49,3% offamilies was classified in low and intermediate levels of effectiveness of family functionality, which is coherent with what was obtained in dimensions and goals and it reflects a deficient incorporation of knowledge to acquire new conducts, problems in effective communication, not sharing experiences and feelings, difficulties to adapt to new values, life styles, absence of relationships with other family systems, deficiencies in collective actions, difficulties to incorporate new knowledge and to transform culture (morphogenesis); the aforementioned causes deterioration in the evolution of the family system.