> ## Documentation Index > Fetch the complete documentation index at: https://docs.mangrovesystems.com/llms.txt > Use this file to discover all available pages before exploring further. # Production Accounting Fundamentals > Key production accounting concepts used in Mangrove #### Project A **Project** defines a set of activities that, as a whole, produces net climate benefits relative to a baseline scenario. All data inputs, accounting, reports and credit inventory live within a project. You can [create a project](getting-started) and configure its models and data inputs. #### Event **Events** are operational activities within a project's boundaries. Each event holds one or more datapoints and represents something that happened at a point in time (e.g., a delivery, a meter reading, a production run). Events are one of the main types of data inputs — they occur with high frequency and their measurements often change from batch to batch. They can be associated with locations, feedstocks, evidence, and other attributes. #### Datapoint A **datapoint** is a single measured value used in production accounting. Events contain datapoints (e.g., mass, flow rate, concentration). Models consume datapoints as inputs and can output new datapoints. #### Evidence **Evidence** is documentation attached to datapoints — delivery tickets, weighbridge slips, meter readings, etc. Evidence supports the audit trail from reporting back to source data. #### Feedstock A feedstock is the raw material used in the production process. In Mangrove, feedstocks are associated to the incoming Events for use in accounting and reporting. #### Batch A **batch** is the main unit of production in a project. Each batch contains the calculations and MRV data supporting that batch’s gross and net carbon activity. Batches are linked to all source data inputs and underlying evidence, and are [generated](generate-batches) by running the accounting dataflow over a chosen period. #### Score A **score** is an output calculation representing the carbon intensity (CI) of a reporting period. Scores are backed by a copy of the executed model. #### Model A **model** is a set of calculations that produce production accounting. Two main types exist: **production models** (operational calculations) and **quantification models** (methodology-specific carbon accounting). Models are built in the Model Editor using a tree of nodes: inputs, intermediate calculations, and outputs. Read more about [production models](models). #### Value Stream A value stream is a way for a project to originate and commercialize its environmental attributes. #### Ledger **Ledgers** (mass accounts) track material or carbon flows across stages of a project. [Mass balance accounting](mass-balance-accounting) uses ledgers to record accumulation and use of material at each stage (e.g., feedstock received, biochar produced, carbon delivered). Not every project needs multiple ledgers — a single ledger is often enough for simpler flows. #### System Ledger A **system ledger** is a ledger auto-created by the platform to track non-physical quantities like [embodied emissions](embodied-emissions) or renewable [instruments](instruments). Unlike user-created mass accounts, system ledgers are managed automatically and have specialized behavior for amortization and inventory tracking. #### Embodied Emission An **embodied emission** is the carbon cost of facilities, equipment, and construction, tracked in a [system ledger](embodied-emissions) and amortized across batches over time or production. Embodied emissions ensure that one-time capital carbon costs are fairly distributed across a project's output. #### Instrument An **instrument** is a renewable energy certificate (REC) or renewable fuel certificate tracked in a [system ledger](instruments). Instruments represent an inventory of environmental attributes that gets consumed as it is allocated to production batches, with balance tracking to prevent double-counting.