The American Library Association recommends this ideal model taken from :  Beyond Proficiency KY State Dept of Education - the following is an edited version.

Model Job Descriptions
(Library Media Specialist and School Library Media Classified Staff)
In order to plan and implement a Library Media Program, a library media specialist must possess comprehensive skills and expertise, which will enhance student achievement.

MODEL JOB DESCRIPTION - LIBRARY MEDIA SPECIALIST
Qualifications: Certification in School Librarianship  MLS
Reports to: Principal
Performance responsibilities:

Administrator of the Library Media Center

Management
Develops short and long-range goals which guide the development of the Library Media Program
Develops and implements policies and procedures for the operation of the Library Media Program (e.g.selection, circulation, scheduling)
Plans and implements technologically advanced facility and program
Coordinates the school’s implementation of KETS if assigned (School Technology Coordinator) or actively serves on committees integrating technology
Prepares and administers budgets to reflect the needs of the entire school community
Evaluates LMC programs, services, facilities and materials to insure optimum use of the library media center and its resources
Meets periodically with administrators to evaluate the Library Media Program
Presents an annual report to the BOE

Organization
Helps with selection, trains, and supervises LMC assistants, student assistants, and adult volunteers, to perform duties efficiently
Helps evaluate the LMC assistant(s)
Selects resources and technology which support the school’s curriculum and educational philosophy
Withdraws obsolete and worn materials
Classifies, catalogs, processes and organizes for circulation the educational media and technology for easy access
Establishes and follows procedures for maintenance and repair of all media
Maintains a current inventory of holdings
Maintains the LMC to be functional, attractive and orderly environment which encourages maximum use, focusing on student achievement
Manages student behavior in a constructive manner

Teacher, Collaborator, and Instructional Partner

Teacher
Teaches information literacy skills as an integral part of units and lessons
Teaches how to use [a Virtual Library .... and electronic resources]

Instructional Partner
Assists teachers and students in applying information resources and information literacy skills into classroom curriculum
Promotes maximum use of the LMC by establishing policies and procedures of flexible access to facilitate and promote student achievement
Serves on committees involved with designing learning activities for students, curriculum revision and/or textbook adoption (e.g., curriculum, textbook, technology, instructional practices...)
Plans and/or participates in special projects or proposals
Plans cooperatively with teachers to integrate research, information retrieval skills, and literature appreciation into the curriculum
Helps teachers develop instructional activities which stress whole language and interdisciplinary strategies

Information Specialist

Professional
Provides professional development for staff
Pursues an on-going effort to learn
Provides access to professional materials and information for school staff
Adheres to and informs faculty and staff of established laws, policies, rules and regulations (including copy right laws)
Submits accurate reports promptly
Participates in various professional organizations and activities which relate to library media and technology (i.e. visits other LMCs, continuing education courses, workshops and conferences; presents at professional meetings)
Promotes the Library Bill of Rights/Intellectual Freedom
Utilizes current research and methods in areas of technology, teaching, learning and library and information science

Communication
Promotes a positive relationship with students, staff and community
Publicizes the LMC programs, services and materials through newsletters, announcements and in other creative ways
Networks with other libraries and shares resources
Submits to administrator(s), BOE and faculty, statistical reports which support Library Media Program goals
Other duties as assigned by principal

The Colorado State Dept of Education requires the following for endorsements for the position of Teacher Librarian:
260.5-R-10.00
Endorsements.  The following shall serve as standards for graduate endorsements.  All endorsement standards shall be reviewed as needed, for continuing appropriateness, applicability, and benefit to Colorado students and schools.

10.01   (Rule number reserved.)

10.02   Teacher Librarian or School Librarian To be endorsed as Teacher Librarian or a School Librarian, the applicant shall meet the following requirements:

10.02   (1)        To be endorsed as a teacher librarian, an applicant shall hold a bachelor’s degree from an accredited institution of higher education; a master’s degree in library science; hold a provisional or professional teaching license; have completed a minimum of one-year of teaching experience in the classroom; and shall have demonstrated knowledge and performance in the areas listed below.

10.02   (2)        To be endorsed as a school librarian, an applicant shall hold a bachelor’s or higher degree from an accredited institution of higher education; and a provisional or professional teaching license; may or may not have classroom teaching experience; and shall have demonstrated knowledge and performance in the areas listed below.

10.02   (3)        The school library educator is knowledgeable about information literacy, collaboration, instructional design, technology, and teaching, and demonstrates the ability to:

10.02   (3)        (a)        Communicate and exhibit to the students, teachers, and administrators an applicable understanding of the learning and teaching, information access and delivery, and the program administration elements of the school library program and its relationship to a school’s education program.

10.02   (3)        (b)        Implement the appropriate school library program elements that include: information literacy, collaboration, instructional design, technology and teaching; children’s and young adults’ literature; copyright, fair use, intellectual freedom, and acceptable use policies; reference services; administration of the library program; leadership and professionalism; and selection, evaluation, and utilization of library media.

10.02   (4)        The school library educator is knowledgeable about information literacy, collaboration,
instructional design, technology and teaching, and demonstrates the ability to:

10.02   (4)        (a)        Ensure that information literacy and educational technology standards are integrated with classroom and library instruction.

10.02   (4)        (b)        Apply the collaborative instructional process with the librarian, technology educator, and classroom teacher which includes planning, scheduling, teaching, implementing, and evaluating.

10.02   (4)        (c)        Model standards-based instruction to support student learning.

10.02   (4)        (d)        Ensure that standards-based lessons are taught that encompass a range of steps including goals, objectives, independent and guided practice, modeling techniques, checks for understanding, and closure.
                                   
10.02   (4)        (e)        Employ a variety of summative and formative assessment and revision techniques. 

10.02   (4)        (f)         Work effectively with classroom teachers and technology educators to promote collaborative planning and curriculum development through the school library program.

10.02   (4)        (g)        Participate with teachers on curriculum writing teams and ensure that information literacy standards are integrated with educational technology and content standards.

10.02   (4)        (h)        Exhibit an understanding of networks and instructional delivery systems. 

10.02   (4)        (i)         Demonstrate an understanding of a fully integrated library automation system for cataloging, accessing the collection, and the circulation of materials.

10.02   (4)        (j)         Exhibit an understanding of troubleshooting and problem solving by analyzing, evaluating, and determining solutions. 

10.02   (4)        (k)        Deliver and access instructional and/or management software and licensed services. 
 
10.02   (5)        The school library educator is knowledgeable about children’s and young adults’
                          literature, and demonstrates the ability to:

10.02   (5)        (a)        Exhibit an understanding of the history, development, and current trends in children’s and/or young adults’ literature. 

10.02   (5)        (b)        Illustrate instructional concepts and the collaborative process through children’s and young adults’ literature.

10.02   (5)        (c)        Exhibit proficiency in children’s and/or young adults’ literature through various methods such as book talks, dramatic readings, storytelling, and creative dramatics.

10.02   (5)        (d)        Develop reading strategies to improve students’ reading based upon reading levels, developmental abilities, and interests.

10.02   (5)        (e)        Identify genres, elements of literary analysis, and criteria for literary award winners.

10.02   (5)        (f)         Identify and describe elements of discrimination in literature such as gender bias, stereotyping, and propaganda.

10.02   (5)        (g)        Model and encourage the love of reading through literature appreciation and reader’s advisory for students and teachers.     

10.02   (6)        The school library educator is knowledgeable about copyright, fair use, intellectual freedom, and acceptable use policies, and demonstrates the ability to:

10.02   (6)        (a)        Apply copyright law.

10.02   (6)        (b)        Implement the guidelines of fair use.

10.02   (6)        (c)        Exhibit a clear understanding of privacy policy statements.

10.02   (6)        (d)        Support the principles of intellectual freedom.

10.02   (6)        (e)        Implement acceptable use policies such as: Internet safety, software licensing, privacy protection, and plagiarism.

10.02   (7)        The school library educator is knowledgeable about reference services, and demonstrates the ability to:

10.02   (7)        (a)        Ensure that the curriculum needs and recreational reading interests of all students and teachers are supported by quality reference services and reference resources.

10.02   (7)        (b)        Identify reference information and exhibit excellent communication skills when participating in the reference interview and when providing appropriate responses to reference inquiries.

10.02   (7)        (c)        Exhibit the ability to teach students and teachers how to access, evaluate, and use the Internet and online library catalogs and online databases.

10.02   (7)        (d)        Participate in interlibrary loan services to successfully acquire resources for the students and teachers to meet their educational needs.

10.02   (7)        (e)        Develop bibliographies, resource lists for instructional units, and other documents as appropriate for meeting the educational needs of the students and teachers. 

10.02   (8)        The school library educator is knowledgeable about administration of the library program, and demonstrates the ability to:

10.02   (8)        (a)        Participate with teachers and administrators to develop and implement a long-range strategic library plan that aligns the school library program’s mission, with the goals and objectives of the school, integrates information literacy into the curriculum, and works collaboratively to deliver services, resources, and activities to meet the needs of the students.

10.02   (8)        (b)        Develop a mission statement, goals, and objectives of the school library program that align with those of the school building and school district.

10.02   (8)        (c)        Develop policies and procedures for the school library program that align with the district policies and procedures.
           
10.02   (8)        (d)        Initiate communication with the school administration and staff about the school library program plan, activities, curriculum, and use of technology.

10.02   (8)        (e)        Utilize standard job descriptions, evaluation practices, and hiring procedures for managing library personnel and volunteer staff.

10.02   (8)        (f)         Prepare, justify, and maintain the school library program budget to ensure funding for the continuous acquisition of standards-based curriculum materials and services.

10.02   (8)        (g)        Develop and utilize an evaluation tool that measures the effectiveness of the school library program including student learning and teaching, and program administration.

10.02   (8)        (h)        Exhibit the skills to assess, analyze, and design a school library media facility for optimal use and functionality to support educational needs of the program. 

10.02   (8)        (i)         Exhibit the use of a planning process for library development using tools such as flow charts and timelines.

10.02   (9)        The school library educator is knowledgeable about leadership and professionalism, and demonstrates the ability to:

10.02   (9)        (a)        Participate as a member in school and district committees, in state, regional and national educational organizations, and in professional library associations.

10.02   (9)        (b)        Apply current trends and issues in the field of school library media and educational technology to address local needs. 

10.02   (9)        (c)        Mentor students, teachers, administrators, and community members and leaders in the effective use of libraries.

10.02   (9)        (d)        Demonstrate diplomacy in organizational politics and the skills to work as part of a team.

10.02   (9)        (e)        Develop strategies for promoting school library programs and services.

10.02   (9)        (f)         Model the principles of ethical behavior to ensure professional integrity. 

10.02   (10)      The school library educator is knowledgeable about selection, evaluation and utilization of library media, and demonstrates the ability to:

10.02   (10)      (a)        Exhibit the skills to use traditional, up-to-date, and electronic selection and collection development tools to ensure the school library media collection supports the standards-based curriculum at all grade levels, in a variety of formats, and for diverse learning styles.

10.02   (10)      (b)        Develop and implement a procedure for student and teacher input for collection development.

 10.02  (10)      (c)        Develop and implement a policy, in collaboration with district and appropriate school personnel, for collection development/selection, weeding criteria, and reconsideration of challenged resources with procedures used to defend the challenged material that is consistent with the mission, goals, and objectives of the school building and school district. 

10.02   (11)      The school library educator is knowledgeable about research and evaluation, and demonstrates the ability to:

10.02   (11)      (a)        Exhibit the skills to conduct traditional and action research. 

10.02   (11)      (b)        Collect, interpret, apply, and evaluate research data and results.

10.02   (11)      (c)        Apply summative and formative assessments.

10.02   (11)      (d)        Apply data driven evidence.

10.02   (12)      The school library educator is knowledgeable about cataloging and classification, and demonstrates the ability to:

10.02   (12)      (a)        Exhibit and manage an organized and school library collection based on the discipline of cataloging and classification.

10.02   (12)      (b)        Exhibit an understanding in using standard tools such as: the Dewey Decimal Classification System, AACR2, MARC, Library of Congress, Sears Subject Headings, and other resources as appropriate for the cataloging and classification of materials.

10.02   (12)      (c)        Exhibit the skills used in the maintenance of bibliographic records.

10.02   (13)      (a)        Have completed a supervised practicum or internship in an elementary and secondary school library at the appropriate grade level(s) for a K-12 endorsement.

10.02   (13)      (b)        The practicum or internship may be waived by the accepted institution upon comparable media experience.     

10.02   (14)      The school library educator shall self-assess effectiveness, as based on student achievement, and pursue continuous professional development, through appropriate activities and coursework, and through participation in relevant professional organizations.