In the simplest terms, one can define an "organization" as group of people who have come together for a particular purpose and "performance" as the action or process of successfully performing a task or function. Here, "organizational performance" would relate to how successfully an organized group of people delivers a task or function. (Of course, there should be agreement on the measurement of success.)
This said, in the real world, organizational performance is the composite result of a great many different tasks or functions, the relative importance of which can—nay, will—vary. Be this as it may, in the private sector, three primary outcomes are quite routinely the subject of investigations: (i) financial performance, (ii) market performance, and (iii) shareholder value performance. (In some cases, production capacity performance is analyzed). In project-based organizations, to give one more example, six parameters are always given weight in methodologies for project management: (i) time, (ii) cost, (iii) human resources, (iv) scope, (v) quality, and (vi) actions. Here, there, and everywhere, everything depends on what it is that must be measured.
More and more recognize also that learning is the key to success—some would even say survival—in today’s organizations. Knowledge should be continuously enriched through both internal and external learning. For this to happen, it is necessary to support and energize organization, people, knowledge, and technology for learning. Building a Learning Organization, available at https://www.researchgate.net/publication/289424484_Building_a_Learning_Organization, elucidates one possible, survey-based, methodology to gauge organizational performance from a learning perspective.