Performance Measures H. Scott Matthews February 3, 2003

Recap of Last Lecture  Looked at Canning and World Bank data on infrastructure capacity and use across developing and developed countries  Period,  Some data holes  Generally inventory, rather than performance data

What is Performance?  Amer. Heritage Dictionary: “the act or manner of filling and obligation or duty”  Oxford: “The accomplishment, execution, carrying out, working out of anything ordered or undertaken; the doing of any action or work  Act or manner: method or ability  Fulfilling: meeting, satisfying  Duty: depends on purpose/objectives - may be strategic, economic, …

Alternative Definitions  “Degree to which a facility serves its users and fulfills the purpose for which it was built or acquired as measured by accumulated quality and length of service it provides to users” (HHU)  Ability to give satisfactory service  Humplick - 5 levels, 4 groups, measures, indicators

Why Care About It?  Performance measures used as tools to do the following (Humplick 94):  Support Management Decisions  Diagnose Potential Problems  Guide suppliers and users  Allocate Resources (aka Economics)  Track Data in Info. Systems

Humplick Framework  5 major levels  Service quality and reliability (users)  Network size and condition (facility)  Op. efficiency & productivity (provider)  Sectoral performance (investment, pricing)  Institutional performance  (Not in Humplick)  Performance measurement/assessment needs to consider both the supply (e.g. condition, inventory) and demand (e.g. usage) sides

Users of Performance Indicators  Facility/Network Users  Service Providers (US DOT, PennDOT)  Facility & Network Providers (firms)  Policy Sector and Institutions (FHWA)

Current Limitations in Assembling Performance Info  Data collected by multiple/different agencies  Data that is collected tends to differ in collection method and context  Type of data  Reliability/Precision  Spatial/temporal frequency  Consistency is variable

Common Characteristics of Infrastructure  Projects/components are parts of networks (e.g. bridge needs road)  Long time horizons (lifespans)  Presence of tradeoffs (build/maintain)  Indivisibility (can’t build half)  Spatial/temporal variability  Essential - to point of being ubiquitous  Expensive (often are one-off solutions)

Common Characteristics (2)  Subject to design standards  Could be DOT, IEEE, etc.  Subject to deterioration  Subject to uncertainty  Exhibit multiple modes of failure  Hierarchical Decision Process  Others?

Approaches to Performance  Condition Assessment  Condition Indices  Reliability Theory  Multi-dimensional Measures

Condition Assessment  Measure type, severity, extent of deterioration  Specific examples or indicators of deterioration used  Subjective ratings  Visual evaluation  Destructive testing  Direct Measurement  Does this sound familiar? (NBI)

Examples  Pavement - total length of cracks per lane mile, roughness, deflection  Bridge decks - chloride content  Pipeline - breaks per mile  Roof - square feet of wet insulation  Electric Power - ?  Communications - ?

Subjective Ratings  Predefined, arbitrary scale (see Grant and Dunker articles)  Requires training to minimize errors and discrepancies across inspectors  Ex: Present Serviceability Rating (PSR) AASHO Road Test: Bad = 0, Good = 5

Testing  Destructive: Requires actual invasive test (or removal) of infrastructure to be compared with reference samples  E.g. cores for density, chemical content  Bending/Breaking trusses  Other: uses technology and sensors to give similar results (e.g. Ground- penetrating radar to detect cracks/defects)

Condition Indices  Developed to address multitude of condition measures  Based on amount of distress or damage, results from non-destructive tests, relationships between use conditions  Condenses ‘vector’ of data into ‘scalar’

Index Requirements  Completeness- covers all aspects of deterioration  Measurable - to ensure consistency and repeatability  Relevance - provides rational quantification of condition  Example: Building Condition Index (BCI) = Total Deferred Maintenance / Replacement Plant Value  Excellent: BCI < 2% Good: 2% < BCI < 5%  Adequate: 5% 60%

Condition Index Limitations  Tries to make performance into one value  Hard to choose right aggregation  May be hard to integrate technology  Anything outside index not included

Reliability Theory  Based on probability of failure  Widely used in high tech industries  Can minimize costs while maximizing reliability