NAME
    Medical::Growth::NHANES_2000 - NHANES 2000 Growth Charts

SYNOPSIS
      use Medical::Growth::NHANES_2000;
      my $handle = Medical::Growth::NHANES_2000->new;
      my $dset = $handle->measure_class_for(measure => 'WtAge',
                                            age_group => 'Infant',
                                            sex => 'Male')
      foreach my $pt (get_infant_data() ) {
        ...
        my $wfa_pct = $dset->pct_for_value($pt->age_mon, $pt->wt_kg);
      }

DESCRIPTION
    Medical::Growth::NHANES_2000 is a measurement system implemented using
    the Medical::Growth framework, that allows you to compare growth
    measurements for children to the National Health and Nutrition
    Examination Survey's (NHANES) 2000 infant and child growth charts
    <http://www.cdc.gov/growthcharts>. Measurement classes are provided for
    each of the datasets published by the CDC. These are typically used to
    compute the percentile for a particular child's measurements relative to
    the NHANES sample.

    In order to compare a particular child's growth measurements to the
    NHANES 2000 norms (the moral equivalent of plotting the measurement on
    the appropriate growth chart), you will need to pick the measure class
    for the growth measurement of interest (the moral equivalent of using
    the right growth chart). While you can use a particular measurement
    class directly by name, Medical::Growth::NHANES_2000 also provides ways
    for you to look up the appopriate measurement class using more flexible
    syntax, as described below.

    Once you have retrieved the measure class, you may use the methods
    available to manipulate specific values documented in the common
    Medical::Growth::NHANES_2000::Base class; these may be called as class
    or instance methods on any of the measurement classes.

  METHODS
    measure_classes
        Returns a list of the names of measurement classes in the
        Medical::Growth::NHANES_2000 system.

    measure_class_name_for(*%criteria*)
        Returns the name of the measurement class matching *%criteria*. No
        check is made that the measurement class is actually available
        (though this will be the case unless something went awry with
        installation of Medical::Growth::NHANES_2000).

        The following elements of *%criteria* are used to identify the
        measurement class. Case is not significant for any of the values.

        measure
            Growth measurement to be examined and basis for comparison. This
            can be a string of the form *measure*" for "*norm*, where
            *measure* is the measurement (one of "Weight", "Height",
            "Length", "Stature", "Head Circumference", or "BMI") and *norm*
            is the norm (one of "Age", "Height", or "Length"). Spaces may be
            replaced with underscores, and "for" may be replaced with "by",
            or the entire preposition just replaced by spaces.

            For convenience, some shorter forms are accepted as well, in the
            form *MeasNorm*. In this case, *Meas* can have the values above,
            but also "Wgt", "Wt", "Hgt", "Ht", "Stat", "Len", "Head", "HC",
            or "OFC", and *Norm* can have the additional values "Hgt", "Ht",
            or "Len".

            Finally, any of "Height", "Length", or "Stature" are mapped to
            "Length" if an infant *age_group* is specified (see below), or
            to "Height" if a child age group is specified.

        age_group
            Age range for the norms to be used. In the NHANES 2000 data,
            this is either infants (ages 0-24 months) or children (ages 2-20
            years). Values of "Infant", "Toddler", "Recumbent", "Neonatal",
            and "Neonate" are taken as "Infant", and values of "Child",
            "School-age", and "Adolescent" are taken as "Child".

            If the value looks like a number rather than a label, it is
            interpreted as an age in months; values of 0-24 map to "Infant"
            and larger values map to "Child".

            The key "age" may be used instead of "age_group"; if both are
            present, "age_group" is preferred.

        sex Sex of the children from whose measurements the desired norms
            were constructed. Values of "Male", "M", "Boy", "B", and 1 map
            to "Male". Values of "Female", "F", "Girl", "G", and 2 map to
            "Female".

        If any of these values are missing or can't be interpreted, an
        exception is thrown.

    have_measure_class_for(*%criteria*)
        Finds the measurement class name for *%criteria* as described above,
        and tries to load the measurement class.

        Returns the name of the measure class if successful, and "undef" if
        the class cannot be loaded.

    measure_class_for(*%criteria*)
        Finds the measurement class name for *%criteria* as described above,
        and loads the measurement class. An exception is thrown if the class
        cannot be loaded.

        Returns a handle for the measurement class, through which its
        methods may be called.

        This method can be called directly, or may be called by delegation
        from "measure_class_for" in Medical::Growth, if the "system" element
        of *%criteria* specifies "NHANES_2000".

  USING NHANES_2000 MEASUREMENT CLASSES
    Once you have a measurement class in hand, you will typically want to do
    one of two things with it:

    Compare a particular child's growth measurements with the NHANES norms.
        You can convert growth measurements to percentiles or Z scores by
        calling pct_for_value or z_for_value, respectively.

    Reconstruct a growth curve
        You can find out what specific growth measurements correspond to a
        given percentile or Z score by calling value_for_pct or value_for_z,
        respectively.

  EXPORT
    None.

SEE ALSO
    Medical::Growth

    <http://www.cdc.gov/growthcharts>

    Moo::Lax (for developers) Medical::Growth::NHANES_2000 is implemented
    using Moo::Lax and friends to avoid the need for compiled dependencies;
    if your code is already using Moose, it should play nicely.

DIAGNOSTICS
    Any message produced by an included package, as well as

    Need to specify measure, age_group, and sex (F)
        One of the required criteria for identifying a measurement class is
        missing.

    Don't understand measure spec (F)
        The value of the "measure" element in *%criteria* wasn't in a known
        format.

    Don't understand measure name (F)
        The growth measurement part of the "measure" element in *%criteria*
        wasn't a known growth measurement.

    Don't understand norm name (F)
        The norm (basis for comparison) part of the "measure" element in
        *%criteria* wasn't a known norm.

    Don't understand age group (F)
        The value of the "age_group" element in *%criteria* wasn't a known
        growth measurement.

    Don't understand sex (F)
        The value of the "age_group" element in *%criteria* wasn't a known
        growth measurement.

BUGS AND CAVEATS
    Are there, for certain, but have yet to be cataloged.

VERSION
    version 1.00

AUTHOR
    Charles Bailey <cbail@cpan.org>

COPYRIGHT AND LICENSE
    Copyright 2012-2014 Charles Bailey.

    This software may be used under the terms of the Artistic License or the
    GNU General Public License, as the user prefers.

ACKNOWLEDGMENT
    The code incorporated into this package was originally written with
    United States federal funding as part of research work done by the
    author at the Children's Hospital of Philadelphia.

