New Mexico State Library

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Public Library Statistics Input/Output Measures - Definition of Terms

 

Legal Service Area Population

    Legal service area” means the geographic area for which a public library has been established to offer services and from which (or on behalf of which) the library derives income. This includes the entire service area of the local public library or library system and does not, for example, include merely the general service area of any one branch. The most recent U.S. Census determines the population of the legal service area if the population figures are given separately for that area (usually a political subdivision of the state.) If the census does not have a discreet population figure for the legal service area, then the state library and the library whose population is at issue will work together to arrive at a mutually acceptable population figure. If this is not possible, the state library in its sole discretion will determine the population for the library’s legal service area. New Mexico Administrative Code (4.5.2) The number of people that reside within the legal service area of the library. The legal service area of a library is the population within the boundaries of the geographic area the library was established to serve.
Staff per 1,000 Population
    = (Total Staff FTE) / (Legal Service Area Population / 1,000) Staff per 1,000 Population measures the level of staffing relative to the legal service area population. It is the number of library staff in Full-time Equivalents divided by the number of persons in that area. Full-time equivalent (FTE) staff is calculated by adding the total number of hours per week worked by all staff and dividing by 40. In this context, full-time means 40 hours per week, regardless of how many hours per week the library is open. This input measure may be relevant whenever the adequacy of library staffing and staff funding are issues. It is particularly useful when the population or geographical area which the library serves increases dramatically. When that happens, there should be a corresponding increase in staff to offset the population increase.
Staff per 10,000 Circulation
    = (Total Staff FTE) / (Circulation / 10,000) Staff per 10,000 Circulation relates the size of the library's staff to the number of items circulated. It is the number of staff in FTEs (see Staff per 1,000 Population) divided by total annual circulation in tens of thousands. This statistic measures staff workload relative to circulation.
Staff per 1,000 Reference Questions
    = (Total Staff FTE) / (Reference Questions / 1,000) Staff per 1,000 Reference Questions relates the size of the library's staff to the number of reference questions the staff handles. It is the number of staff in FTEs (see Staff per 1,000 Population) divided by total annual reference questions. This statistic measures staff work load relative to reference services provided.
Print Volumes per Capita
    = Print Volumes Held / Legal Service Area Population Print Volumes per Capita relates the number of volumes or units in the library's collection to the number of persons it was established to serve. It is the number of print volumes held by the library divided by its legal service area population. This figure indicates the average number of volumes held for each person in the library's legal service area population. This input measure may be relevant whenever the size of the library's collection is an issue. It is particularly useful when the population or geographical area which the library is established to serve changes dramatically. For example, in the latter case, there should be corresponding increases in Materials Expenditures as well as Volumes Held just to maintain the existing ratio of holdings to persons served.
Subscriptions per 1,000 Population
    = (Serial Subscriptions) / (Legal Service Area Population / 1,000) Subscriptions per 1,000 Population relates the number of current serial subscriptions carried by the library to the size of the population it serves. It is the number of current serial subscriptions divided by the population served divided by one thousand. This statistic is a measure of the size of the library's current periodicals collection relative to the population it serves.
Videos per 1,000 Population
    = Videos Held / (Legal Service Area Population / 1,000) Videos per 1,000 Population relates the number of video materials in the library's collection to the size of the population it serves. It is the number of video cassettes or disks divided by the population served in thousands. This statistic is a measure of the size of the library's video collection relative to the population it serves.
Collection Expenditures per Capita
    = (Collection Expenditures) / (Legal Service Area Population) Collection Expenditures per Capita relates library funds spent on materials for the collection (e.g., books, periodicals, and non print items such as audio and video cassettes) to the number of persons the library was established to serve. It is the dollar amount spent on materials divided by the library's legal service area population, and indicates the average cost per person of purchasing newly acquired materials. This figure does not take into account the cost of processing library materials. Collection Expenditures per Capita is relevant whenever the size or usefulness of the collection is an issue. When addressing this issue, relate other input measures indicating the quantity of materials available, such as Volumes Held per Capita; also relate output measures that indicate the usefulness of materials, such as Circulation per Capita, and Turnover Rate. It is also important to review Collection Expenditures per Capita whenever the population of the library's legal service area changes quickly. Staff Expenditures as a Percent of Operating Expenditures = Staff Expenditures / Total Operating Expenditures Staff Expenditures as a Percent of Operating Expenditures is the sum of all staff expenditures for salaries, wages, and benefits divided by the sum of all operating expenditures for staff, materials, and other purposes. This measure indicates the proportion of the library's annual operating expenditures that is spent to compensate staff. Generally, this figure comprises the single largest proportion of operating expenditures. If this figure is extremely high, however, it may indicate a lack of adequate funding for other aspects of library operations; and, if extremely low, it may indicate a lack of commitment to having professionally trained library staff.
Collection Expenditures as a Percent of Operating Expenditures
    = (Collection Expenditures) / (Total Operating Expenditures) Collection Expenditures as a Percent of Operating Expenditures relates the amount spent on the library's collection to what is spent for overall operations. It is the cost of library materials divided by the amount spent for all operating expenses including materials costs. This measure indicates the proportion of the library's operating expenditures which is set aside for materials. This may indicate a library's commitment to its collection. However, an extremely high figure on this measure can also indicate a library's lack of commitment to paying staff, which is usually a major cost. To interpret this measure, take into account "other operating expenditures." A library may pay large bills for online utilities and telecommunications services for database searching. For comparisons, use libraries which have similar "other" expenses.
Local Income per Capita
    = (Total Local Income) / (Legal Service Area Population) Local Income per Capita is perhaps the best single measure of the library's financial support, as the vast majority of operating income comes from local sources. This is the total local income amount (from city, county, district, or other sources) divided by the number of persons in the library's Legal Service Area. Knowing the extent to which libraries are supported by their local funding base is valuable information for public librarians and their governing boards when submitting and defending budgets.
Library Visits per Capita
    = Library Visits/ Legal Service Area Population Library Visits per Capita relates the number of annual library visits to the number of persons the library is established to serve. It is attendance at the library during a year divided by the library's legal service area population. This measure may be estimated by counting the number of persons (excluding library staff) who enter -- or, if preferred, leave the library during a typical week. A typical week is one during which the library is open its regular hours (no holidays) and which is neither extraordinarily busy nor slow. Because Library Visits per Capita indicates the average number of library visits per person served, it is a better measure of public awareness and use of the library than Registration per Capita. Because registration statistics may be out of date and, therefore, questionably valid, attendance statistics reflect actual visits to the library. Taken with Reference, Circulation per Capita, and Program Attendance per 1,000 Populatoin, Library Visits per Capita can be used to develop an annual profile of library use.
Circulation per Capita
    = Circulation / Legal Service Area Population Circulation per Capita relates the number of library materials lent to the number of persons the library serves. It is annual circulation divided by the library's legal service area population, and indicates the average number of loans made to each resident annually. Lower Circulation per Capita can be a result of lower Materials Expenditures and Volumes Held per Capita.
Reference Questions per Capita
    = Reference Questions / (Legal Service Area Population Reference Questions per Capita relates the annual number of information contacts with a staff member using information sources to the number of persons the library is established to serve. It is the number of reference transactions per year divided by the library's legal service area population. This measure indicates the average number of times a resident of the library's legal service area received staff assistance in using information sources available at or accessible through the library. Reference Questions per Capita may be relevant whenever the impact of reference service is an issue. Comparing this figure to Circulation per Capita may be useful in evaluating the reference desk as an access point for information available in the local collection.
Evening & Weekend Hours as Percent of Hours Open
    = (Evening Hours Open + Weekend Hours Open) / (Total Hours Open) Evening & Weekend Hours as Percent of Hours Open shows the percent of hours the library is open after 5 o'clock p.m. and on the weekends, compared to all hours the library is open to the public. (See also Public Service Hours Open per Week, below.)
Public Service Hours Open per Week
    Public Service Hours Open per Week is a simple count of hours that the library is staffed and open to the public. For libraries with multiple outlets, this is the total number of hours open per week for all outlets combined.
Turnover Rate
    = Circulation / Volumes Held Turnover Rate relates the number of materials checked out to the size of the collection. It is the number of materials circulated divided by the number of volumes held. Turnover rate indicates how often each item in the collection was lent, thus this measure is relevant to use of the collection. It may be useful to compare this figure to selected inputs such as volumes held per capita, and outputs such as circulation per capita.
Total Program Attendance per 1,000 Population
    = (Total Program Attendance) / (Legal Service Area Population) Total Program Attendance per 1,000 Population relates attendance of scheduled presentations which are sponsored by the library (on or off library premises) to the population the library is established to serve. It is program attendance divided by the library's legal service area population in thousands. It indicates the number of residents per 1,000 in the library's legal service area who attended a library program during the year. This output measure may be relevant whenever the library needs to demonstrate its services to groups.
Used with permission from the Colorado State Library, Library Research Service http://www.lrs.org