Attributes can be thought of as:
A piece of information describing a map feature. The attributes of a census tract, for example, might include its area, population, and average per capita income.
A characteristic of a geographic feature described by numbers, characters, images, and CAD drawings, typically stored in tabular format and linked to the feature by a user-assigned identifier. For example, the attributes of a well might include depth and gallons per minute.
A column in a table.
A dynamic attribute is an attribute that is automatically updated as changes are made in the analysis using the unique capabilities of Scenario 360. For example, a proposed road layer may contain dynamic attributes for length, pavement type, intersecting slopes, and construction costs. As each new road segment is added or modified, each of these dynamic attributes will be updated automatically or, if you choose, on demand (manually) using User Input dialogs or Scenario Sketch styles.
A formula is associated with each dynamic attribute. The formula specifies how the attribute is calculated. A value is calculated separately for each feature within the data layer (e.g., area of each parcel or distance from each structure to its nearest transit stop). For information on executing attribute formulas, see Running attribute formulas.
A dynamic attribute can be defined for any dynamic feature layer or database table layer. A dynamic attribute will have the same formula in all scenarios, but it may take on different values for each feature and each scenario.
Because dynamic layers are more complex, they take up more hard drive space. Don't make attributes or layers dynamic unless they need to be.
Keep the list of attributes in a dynamic layer as short as possible. Delete used fields - especially the cov_#, cov_id, right_poly, etc. fields from the coverage format that are not being used by the geodatabase format.
Use number fields whenever possible.
Set string field size to least amount needed (i.e., don't use 255 length string fields when 10 will do).
Keep features that are common to all scenarios and not really needed for analysis in reference layers (e.g. your roads layer contains major highways but your analysis is concerned only with local roads. In this case, make a reference layer for major highways and a dynamic layer for local roads).