NAICS Catch-All Glossary

541618 is the residual code for management consulting work that doesn't fit the four specialized management-consulting codes. Contracting officers use it when scope crosses sub-disciplines or sits in regulatory, telecom, agricultural, or specialty operations.

Not included: If the work is scientific/technical consulting (not management), 541690 is the right home. If it's broader than any 5419 sub-code, 541990 fits.

541519 catches IT services that aren't custom programming, systems design, facilities management, or computer training - typically disaster recovery, software installation advisory, IT operations support, and IV&V.

Not included: Computer training falls under 611420, not 541519. Telecom infrastructure consulting typically maps to 541618 or 517-series codes.

541690 covers scientific and technical consulting that doesn't fall under environmental consulting or one of the management-consulting codes - including AI governance, cybersecurity governance, privacy, and cross-disciplinary technical advisory.

Not included: Engineering services (541330), R&D (5417), and surveying/testing labs (541370, 541380) are separate codes - not 541690.

541990 is the broadest residual in the 5419 subsector - it catches professional, scientific, and technical services that don't fit any other 5419 sibling code. Use it for embedded analyst support, mixed-discipline research, or genuinely bespoke advisory.

Not included: If the work fits a specific 5419 code (e.g., 541611, 541618, 541690), pick the specific code first. 541990 is the last resort, not the first choice.