While organizations want to develop software products with reduced cost and flexible scope, stories about the applicability of agile practices to improve project development and performance in the software industry are scarce and focused on specific methodologies such as Scrum and XP. Given these facts, this paper aims to investigate, through practitioners' perceptions of value, which agile practices are being used to improve two performance criteria for software projects-cost and scope. Using a multivariate statistical technique known as Exploratory Factor Analysis (EFA), the results suggest that the use of agile practices can be represented in factors which describe different applications in software development process to improve cost and scope. Also, we conclude that some agile practices should be used together in order to get better efficiency on cost and scope in four development aspects: improving (a) team abilities, (b)management of requirements, (c) quality of the code developed, and (d) delivery of software on-budget and on-time.