Purpose This paper aims to build and analyse the validity and reliability of a measurement scale that establishes the relationship between conditions of knowledge management, innovation capability and firm performance in Colombian New Technology-Based Firms (NTBFs). Design/methodology/approach An instrumental study was carried out because of the design and revision of the psychometric properties of a scale. The techniques used for the statistical analysis were carried out in three sequences, namely, the first consists in collecting validity evidence based on test content; the second in an exploratory and confirmatory factor analysis to gather validity evidence based on internal structure; and third, estimate the test reliability of internal consistency through omega coefficient. Findings The results obtained show that the proposed measurement scale complies with the psychometrics properties required for a measurement instrument in social sciences. Originality/value The model of measurement scale, including three important constructs for firms, namely, conditions of knowledge management, innovation capability and firm performance, were not tested before for NTBFs. In this way, the present study contributes to the business sector. Finally, this scale can be useful to measure the variables studied in NTBFs of other countries, considering strategic purpose, flexible structure, information and communications technology and internal environment as internal conditions, and, as an external condition, the competitive environment, as conditions of knowledge management; exploration, exploitation and organizational ambidexterity as elements of innovation capability; and the non-economic performance and economic performance as one-dimensional structures.