The Beatmap Appreciation Team (BAT, previously known as the Beatmap Approval Team) was a group responsible for overseeing the beatmap ranking and disqualification processes in the forum modding system. BAT members also possessed basic tools for in-game and forum moderation used by the Global Moderation Team (GMT).
Together with the Mapping Assistance Team (MAT) until the two merged in April 2013, the BAT were responsible for evaluating the quality of beatmaps and deciding what content made its way into the Ranked section.
From the 15th of May, 2013 onwards, the BAT were regulated by a group of BAT Managers (BATm) who oversaw their operation and provided guidance where necessary.
The BAT was formed as early as 2008.
Prospective BAT members could apply to join by submitting a sample of their modding activity and experience during allocated cycles, and would be reviewed by existing BAT members (and later also the BAT Managers) for their suitability as a BAT member. The frequency of application cycles was determined by the BAT Managers. The BAT Managers also sometimes directly invited users with exceptional potential.
On the 21st of August, 2014, existing members of the BAT were given the option of remaining in the BAT to focus on beatmap qualification (giving up their moderation powers and responsibilities in the process), or transitioning to the new Quality Assurance Team (QAT). The remaining BAT members would focus on the process of nominating beatmaps for the Ranked category, while the QAT would focus on checking these Qualified maps, and disqualifying any they deemed to be breaking the ranking criteria, or otherwise lacking in quality.
On the 31st of January, 2015, the group was renamed the "Beatmap Appreciators", and shortly after the "Beatmap Nomination Group" (BNG), which later became the Beatmap Nominators. At this time, the rules on admission of new members to the BAT were changed to allow entry via application only on a monthly basis.
Applications from this point onwards were evaluated in a more quantitative fashion, with each applicant's activity over the course of several months taken into account more significantly than the endorsement of existing BAT members. This had the effect of making the new BNG significantly more accessible and transparent to prospective applicants and the mapping and modding community as a whole.