It should be testers not 'tester'. Prior to a release of a software/computer sytem, a test lead works in conjunction and simultenously with development as a software/computer system is being developed. He/she conducts ad-hoc and unit testing to verify system's functionality or a specific requirement is met and that the features that have been tested before are currently working (i.e. codes have not been broken). During this period, deviations (bugs) should be logged and on-going communication with development should be conducted on a daily basis as nescessary. When the system is moved to QA environment from Development environment, formal testing shall be done. The role of the test lead here is to strategize the test plan for the system. Once that is done, the test lead shall then coordinate a team of test executors to run the test scripts. Upon the success of the testing in QA, the system shall then be released with a release note which captures identified knowns issues and their resolutions e.g. disabling issued modules, workarounds..ect.