Yours

4.2: OPL Header

The ADAPT WeBWorK Handbook · LibreTexts

0%

Contents

    Text

    Size
    100%
    Theme
    Typeface
    Line length
    Spacing

    From LibreTexts, under CC BY 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    This section explains the OPL header for the worked example and shows how to pick biology-appropriate classification tags. The header comes before DOCUMENT() and acts as the metadata "section zero" for the problem.

    Use this page when: you are writing metadata for a new problem or reviewing a problem before publishing.

    Worked example header

    This is the complete OPL header for the worked example in Chapter 4.

    ## TITLE('Color choice using radio buttons')
## DESCRIPTION
## Select the correct color label from two radio button formats and confirm the choice labels.
## ENDDESCRIPTION
## KEYWORDS('radio buttons','choice list','PGML prompt')
## DBsubject('Biochemistry')
## DBchapter('Lab techniques')
## DBsection('Reporting conventions')
## Level(2)
## Date('2026-01-28')
## Author('Example author')
## Institution('Example institution')
## Language(en)

    Customize the TITLE, DESCRIPTION, KEYWORDS, and classification fields to match your problem's content and subject area.

    Field checklist

    Field checklist: field, what it should contain, and common mistakes.
    Field What it should contain Common mistakes
    TITLE Short, student-facing task title. Too long or story-like titles.
    DESCRIPTION 2 to 3 sentences describing the task and constraints. No constraints or overly long explanations.
    KEYWORDS 3 to 5 concept or technique keywords. Story nouns instead of concepts.
    DBsubject/DBchapter/DBsection Life science classification strings. Leaving these blank or too generic.
    Level Bloom's taxonomy level (1-6). Omitted or set to wrong cognitive level.
    Date/Author/Institution Attribution fields for reuse. Omitted attribution.
    Language ISO 639-1 code (e.g., en). Omitted entirely.

    How this header fits into the problem structure

    The OPL header is "section zero" - it comes before DOCUMENT() and exists outside the traditional four-section structure (Preamble, Setup, Statement, Solution). Think of it as the problem's passport: it makes the problem searchable, classifiable, and reusable in problem banks.

    Five-section reality

    1. Section 0: OPL Header (metadata comments, before DOCUMENT)
    2. Section 1: Preamble (DOCUMENT through loadMacros)
    3. Section 2: Setup (Perl code before PGML)
    4. Section 3: Statement (BEGIN_PGML / END_PGML)
    5. Section 4: Solution (optional BEGIN_PGML_SOLUTION / END_PGML_SOLUTION)

    Traditional PG documentation only lists four sections because it omits the OPL header. However, for long-term reuse and problem bank classification, the header is essential.

    Choosing biology classifications

    The worked example uses DBsubject('Biochemistry') because the problem context is lab-focused. Here's how to choose classifications for other biology problems.

    Classification decision guide

    Classification decision guide reference.
    Problem type DBsubject DBchapter suggestion
    Dilution calculations, spectrophotometry, gel analysis Laboratory Techniques Solution preparation, Protein analysis, DNA analysis
    Enzyme kinetics, buffer pH, protein structure Biochemistry Enzymes, Acids and bases, Proteins
    Punnett squares, pedigrees, linkage Genetics Mendelian inheritance, Pedigree analysis, Linkage
    Cell signaling, membrane transport, organelles Cell Biology Signal transduction, Membranes, Organelles
    DNA replication, transcription, translation Biology - molecular DNA replication, Gene expression, Translation

    Classification guidelines

    • Start with course context: If the problem is for a Biochemistry course, use DBsubject('Biochemistry') even if it involves lab techniques.
    • Use existing tags: Search your repository for similar problems and copy the exact classification strings to maintain consistency.
    • Be specific in DBsection: Instead of "General concepts", use "Michaelis-Menten kinetics" or "Serial dilutions".
    • Avoid empty strings: Never leave DBsubject, DBchapter, or DBsection blank. Choose the closest existing label and revise later if needed.

    Quick reference: Header fields explained

    TITLE field

    Student-facing title that appears in problem listings. Keep it under 80 characters and focus on the task, not the story wrapper. For detailed guidance and good/bad examples, see OPL Header and Metadata.

    Example for worked problem: TITLE('Color choice using radio buttons')

    DESCRIPTION block

    Instructor-facing summary (2-3 sentences) that describes the task, constraints (units, rounding), and provenance if adapted from another source. For templates and biology examples, see OPL Header and Metadata.

    Example for worked problem: The description mentions "radio button formats" and "choice labels" to clarify what students will interact with.

    KEYWORDS field

    3-5 technique or concept keywords that make the problem searchable. Avoid story nouns and generic terms. For keyword selection process and biology examples, see OPL Header and Metadata.

    Example for worked problem: KEYWORDS('radio buttons','choice list','PGML prompt') focuses on interaction type and PGML features, not biology content (since this is a demonstration problem).

    Attribution fields

    Date, Author, and Institution provide credit and help track provenance for long-term reuse. Always include these fields, even for internal problems.

    Textbook provenance fields

    When a problem is adapted from a textbook or other source, use these fields to track the original. Number the tags (TitleText1, TitleText2, etc.) to map to multiple texts when appropriate.

    ## TitleText1('Title of source')
## EditionText1('Edition')
## AuthorText1('Author(s)')
## Section1('Section identifier')
## Problem1('Problem identifier')

    If adapted, also state that in the DESCRIPTION block (e.g., "Adapted from ...").

    Level field: Bloom's taxonomy

    The Level(...) field uses a 1-6 scale aligned to Bloom's revised taxonomy. This field classifies the cognitive demand of the problem and is required.

    Level field: Bloom's taxonomy: level, category, and description.
    Level Category Description
    1 Remember Recall a term, definition, or basic fact. Verbs: recall, define, label, list, identify.
    2 Understand Describe, explain, or classify a concept. Verbs: explain, summarize, interpret, classify.
    3 Apply Use rules or methods in a direct way. Verbs: apply, use, determine, solve.
    4 Analyze Interpret data and connect to conclusions. Verbs: analyze, compare, contrast, infer.
    5 Evaluate Justify choices or critique evidence. Verbs: evaluate, justify, critique, defend.
    6 Create Design or propose something new. Verbs: design, propose, formulate, develop.

    The worked example is Level 2 (Understand) because students classify color labels from given options. For the full Bloom's taxonomy scale with biology-specific examples, see OPL Header and Metadata.

    Language field

    Use ISO 639-1 language codes. This field is required. For English:

    ## Language(en)

    License comments

    Include a license comment block at the top of every problem file for proper attribution and reuse. OPL does not define a standard license tag. Use plain comment lines (single #) to state licensing. This is not an OPL tag but is required for the repository.

    # This work is licensed under CC BY 4.0 (Creative Commons Attribution 4.0
# International License).
# https://creativecommons.org/licenses/by/4.0/
# Source code portions are licensed under LGPLv3.

    Cross-references for detailed guidance

    • OPL Header and Metadata: Comprehensive OPL header guidance with biology examples, decision trees, and good/bad comparisons.
    • Minimal Templates: Complete problem templates with pre-filled OPL headers you can copy and adapt.
    • Next sections in Chapter 4: After the header, see Preamble, Setup, Statement for how each section builds on the metadata.

    Common mistakes in problem context

    • Forgetting to update the header after modifying the problem: If you change a dilution problem to a genetics problem, update DBsubject, DBchapter, KEYWORDS, and DESCRIPTION.
    • Copying header from unrelated problem: Always customize TITLE, DESCRIPTION, and classification tags to match the new problem's actual content.
    • Smart quotes in header: Use plain ASCII quotes ('), not curly quotes (' or '). Smart quotes break OPL parsing tools.
    • Empty classification fields: Never leave DBsubject, DBchapter, or DBsection empty. Pick the closest existing tag and revise later if needed.

    Apply it today

    • Check that every problem has TITLE and DESCRIPTION before you edit the prompt.
    • Update the DBsubject tags whenever the scientific context changes.
    • Use existing classification strings from your repository to maintain consistency.
    • Cross-reference OPL Header and Metadata for detailed field guidance and biology examples.
    • Use templates from Minimal Templates for pre-filled OPL headers.

    This page titled 4.2: OPL Header was last modified on Fri, 27 Feb 2026 15:21:24 GMT and is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by Neil R. Voss.