According to PMI, a model is "a way of thinking to explain a process, framework, or phenomenon", a method is "the means for achieving an outcome, output, result, or project deliverable", and an artifact is a template, document, output, or project deliverable. 

As we see from the tailoring processes, a project manager is completely limitless to tailor the processes and use whatever model, method, or artifact according to the needs of the project. However,  there are options to make the selection process easier by providing a brief introduction of models, methods, and artifacts.

A method, model, or artifact used in a project,
  • should provide value that is worth the effort,
  • should be useful,
  • should serve the needs of the project team instead of individual
Commonly used models are;
  • MOTIVATION MODELS
  • CHANGE MODELS
  • COMPLEXITY MODELS
    • Cynefin Framework
    • Stacey Matrix
  • PROJECT TEAM DEVELOPMENT MODELS
Commonly used methods are;
  • ESTIMATING METHODS
    • Affinity grouping.
    • Analogous estimating.
    • Function point.
    • Multipoint estimating.
    • Parametric estimating.
    • Relative estimating.
    • Single-point estimating.
    • Story point estimating.
    • Wideband Delphi
  • MEETINGS AND EVENTS
    • Backlog refinement. 
    • Bidder conference. 
    • Change control board. 
    • Daily standup. 
    • Iteration planning. 
    • Iteration review. 
    • Kickoff.
    • Lessons learned meeting
    • Planning meeting
    • Project closeout
    • Project review
    • Release planning
    • Retrospective
    • Risk review 
    • Status meeting 
    • Steering committee
  • OTHER METHODS
    • Impact mapping
    • Modeling
    • Net Promoter Score (NPS®)
    • Prioritization schema
    • Timebox
Commonly used artifacts are;
  • STRATEGY ARTIFACTS
  • LOGS AND REGISTERS
  • HIERARCHY CHARTS
  • AGREEMENTS AND CONTRACTS
    • Fixed-price contracts
    • Cost-reimbursable contracts
    • Time and materials (T&M)
    • Indefinite delivery indefinite quantity (IDIQ)
    • Other agreements
  • OTHER ARTIFACTS
    • Activity list
    • Bid documents
    • Metrics
    • Project calendar
    • Requirements documentation
    • Project team charter
    • User story