HALF-STEP/DUAL-TRACKING SCHEDULE UPDATES - Half-step, also known as dual-tracking, is a schedule update maintenance method designed to isolate the effect of actual progress in an update period from changes made to the CPM schedule itself. See also: SCHEDULE UPDATE. (June 2018) HAMMOCK ACTIVITY - An aggregate or summary activity. All related activities are tied as one summary activity and reported at the summary level. It has no duration of its own but derives one from the time difference between the two points to which it is connected. The hammock activity does not affect schedule dates of the activities it spans. (June 2007) HANGER - An unintended break in a network path. (June 2007) HAUL DISTANCE - The distance measured along the center line or most direct practical route between the center of mass of excavation and the center of mass finally placed. It is the average distance material is moved by a vehicle. (November 1990) HEDGE - In master production scheduling, a quantity of stock used to protect against uncertainty in demand. The hedge is similar to safety stock, except that a hedge has the dimension of timing as well as amount. (November 1990) HEURISTIC - An experience-based technique used as a general way of solving a problem, e.g., Rule of Thumb. (December 2011) HIERARCHICAL CODING STRUCTURE - A coding system that can be represented as a multi-level tree structure in which every code except those at the top of the tree has a parent code. (June 2007) HIERARCHICAL PLANNING - Planning approach where each managerial level breaks planning tasks down into those activities that must be done at that level. Typically, upper-level planning establishes the objectives for the next lower- level manager's planning. (June 2007) HIERARCHY (HIERARCHICAL) - A ranking of items according to their logical relationships. (June 2007) HIGHEST AND BEST USE - The valuation concept that requires consideration of all appropriate purposes or uses of the subject property in order to determine the most profitable likely utilization. (November 1990) HISTORIC RECORDS - Documentation from past projects that can be used to predict trends, analyze feasibility and highlight problem areas/pitfalls on future similar projects. (June 2007) HISTORICAL DATABASE - Records accumulating past project experience stored as data for use in planning, estimating, forecasting and predicting future events. Often includes data that has been processed so as to facilitate planning and other purposes such as validation and benchmarking (e.g., metrics, etc). (June 2007) HOLDING TIME - Time that an item is not operational so that it may be serviced. (November 1990) HOLIDAY - An otherwise valid working day that has been designated as exempt. Holidays typically occur on a yearly basis. In the US, holidays may include New Years’ Day, Memorial Day, Independence Day, Labor Day, Thanksgiving and Christmas. (June 2007) HOME OFFICE COST - Those necessary costs, typically not incurred at the project site, involved in the conduct of everyday business, which can be directly assigned to specific projects, processes, or end products, such as engineering, procurement, expediting, legal fees, auditor fees inspection, estimating, cost control, taxes, travel, reproduction, communications, etc. (June 2007) HYPERCRITICAL - A condition when an imposed date has been set such that the critical path leading to that point is too long to finish by that date. The critical path then becomes hypercritical and possesses negative float. (June 2007) HYPERCRITICAL ACTIVITIES - Activities on the critical path with negative float. This can be achieved through the imposition of constraints such as target dates. (June 2007)