Given software release deadlines, the early stages of a structured software development life cycle (SDLC) project can run behind schedule, shrinking the time allowed for performing adequate testing. This situation urges the need to start testing early and manage the testing effort efficiently. Our research examines how to assess the ways activities in the earlier stages of a project are progressing relative to their effect on the efficiency and effectiveness of the latter SDLC stage of testing. We build on the design for testability perspective by introducing the manage for testability perspective, where software testability reflects whether the activities of the SDLC process are progressing in ways that support the testing team with the appropriate software project information and testable designs to enable finding software product problems if they exist during the testing stage. To address this challenge, we develop a software testing assessment to manage project testability during the earlier stages of the SDLC and we propose using the assessment as part of a testability measurement system. The software testing assessment is designed to provide testing managers information they need: (1) to influence pre-testing activities in ways that ultimately increase testing efficiency and effectiveness, and (2) to plan testing resources that facilitate an efficient and effective testing stage. We developed specific software testing assessment measures through several rounds of interviews with key informants (i.e., testing managers at a global transportation company). To support the assessment's usefulness and application, we present data collected for the measures for large-scale structured software development projects and post-data collection debriefing sessions with senior testing leaders.