I think the first question that needs to be addressed is what exactly is an interior designer and how does it differ from being a "decorator"?
The NCIDQ website offers some great answer to both these questions.
Here is their definition of an interior designer:
NCIDQ Definition Of Interior Design
Interior design is a multi-faceted profession in which creative and technical solutions are applied within a structure to achieve a built interior environment. These solutions are functional, enhance the quality of life and culture of the occupants, and are aesthetically attractive. Designs are created in response to and coordinated with the building shell, and acknowledge the physical location and social context of the project. Designs must adhere to code and regulatory requirements, and encourage the principles of environmental sustainability. The interior design process follows a systematic and coordinated methodology, including research, analysis and integration of knowledge into the creative process, whereby the needs and resources of the client are satisfied to produce an interior space that fulfills the project goals.
Interior design includes a scope of services performed by a professional design practitioner, qualified by means of education, experience, and examination, to protect and enhance the life, health, safety and welfare of the public. These services may include any or all of the following tasks:
- Research and analysis of the client's goals and requirements; and development of documents, drawings and diagrams that outline those needs;
- Formulation of preliminary space plans and two and three dimensional design concept studies and sketches that integrate the client's program needs and are based on knowledge of the principles of interior design and theories of human behavior;
- Confirmation that preliminary space plans and design concepts are safe, functional, aesthetically appropriate, and meet all public health, safety and welfare requirements, including code, accessibility, environmental, and sustainability guidelines;
- Selection of colors, materials and finishes to appropriately convey the design concept, and to meet socio-psychological , functional, maintenance, life-cycle performance, environmental, and safety requirements;
- Selection and specification of furniture, fixtures, equipment and millwork, including layout drawings and detailed product description; and provision of contract documentation to facilitate pricing, procurement and installation of furniture;
- Provision of project management services, including preparation of project budgets and schedules;
- Preparation of construction documents, consisting of plans, elevations, details and specifications, to illustrate non-structural and/or non-seismic partition layouts; power and communications locations; reflected ceiling plans and lighting designs; materials and finishes; and furniture layouts;
- Preparation of construction documents to adhere to regional building and fire codes, municipal codes, and any other jurisdictional statutes, regulations and guidelines applicable to the interior space;
- Coordination and collaboration with other allied design professionals who may be retained to provide consulting services, including but not limited to architects; structural, mechanical and electrical engineers, and various specialty consultants;
- Confirmation that construction documents for non-structural and/or non-seismic construction are signed and sealed by the responsible interior designer, as applicable to jurisdictional requirements for filing with code enforcement officials;
- Administration of contract documents, bids and negotiations as the client's agent;
- Observation and reporting on the implementation of projects while in progress and upon completion, as a representative of and on behalf of the client; and conducting post-occupancy evaluation reports.
The NCIDQ Examination and Certificate
Completion of the NCIDQ Examination recognizes that an individual has met minimum competency standards to protect the health, safety and welfare of the public in the practice of interior design. NCIDQ's role includes the establishment of standards for the certificate which includes minimum qualifications for education and experience and the administration of a minimum competency examination.
Passage of the exam is a requirement for licensure in all NCIDQ member jurisdictions. The exam also serves as a qualifier for professional membership within interior design organizations and, for non-affiliates, represents a voluntary individual accomplishment.
Candidates receive an individual NCIDQ Certificate number when they successfully complete the examination cycle, except for Texas candidates who are required to apply for the examination through their state board. In order for Texas candidates to receive their NCIDQ Certificate number, they must apply to NCIDQ once they passed all exam sections. The Certificate identifies the qualified practitioner, ensures recognition of expertise and assists development and self-improvement through the individual's understanding of a body of knowledge and a set of professional standards.