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Oracle Data Warehouses and Return on Investment (ROI)

Oracle Data Warehouse Tips by Burleson Consulting


A data warehouse project should never begin unless management feels that the benefits of a data warehouse outweigh the cost. With that basic assumption under our belts, let?s look at some of the differences between how the ROI for a data warehouse compares to the ROI for other information systems development projects.

The International Data Corporation (IDC) conducted a survey in 1996 that studied ROI for data warehouse projects. IDC found the following trends in data warehouse projects:

*     Very fast payback--The average ROI for a data warehouse is far above the industry average. Corporations with complex organizational and customer environments benefit the most. IDC found that more than 60 percent of data warehouse projects have a payback period of less than 2 years.

*     Large ROI variance--The variance of ROI among organizations ranges from 3 percent to 1,800 percent. The low ROI values are attributed to very expensive data warehouse projects that take several years to develop and have a small amount of usage.

*     Higher ROI for data marts--Larger data warehouses have a lower ROI than smaller data warehouses. IDC found that databases larger than 200 GB had smaller ROI values than smaller data warehouses. This difference is attributed to the extra work required to integrate and maintain the diverse data sources.

*     Application area differences--There are differences among data warehouse ROIs based on the type of organization that develops the data warehouse. Data warehouses designed to support engineering and operations tend to have the highest ROI. This makes sense because, historically, manufacturing organizations have been among the first to embrace data warehousing. The IDC study also shows that European companies developing data warehouses lag behind American companies by a 100 percent margin of ROI, with European companies averaging 340 percent ROI and American companies averaging 440 percent ROI.

The overall finding in the IDC study showed that data warehouses are popular primarily because of the fast payback period for the dollar investment. Interestingly, the payback period most likely will become even shorter as data warehouse developers create more intelligent queries against their data and become more adept at locating and analyzing trend information.

Warehouse Project Management

When embarking on a data warehousing project, many pitfalls can cripple the project. Characteristics of successful data warehouse projects generally include the following aspects:

*     Clear business justification for the project--Measurable benefits must be defined for a warehouse project (e.g., sales will increase by 10 percent, customer retention will increase by 15 percent). Warehouses are expensive, and the project must be able to measure the benefits.

*     Staff is properly trained--Warehousing involves many new technologies, including SMP, MPP, and MDDB. The staff must be trained and comfortable with the new tools.

*     Insuring data quality and consistency--Warehouses deal with historical data from a variety of sources, so care must be taken to create a metadata manager that ensures common data definitions and records changes of historical data definitions.

*     Insuring subject privacy--Gathering data from many sources can lead to privacy violations. A good example of privacy violation is the hotel chain that targeted frequent hotel customers and sent a frequent-user coupon to their home addresses. Some spouses intercepted these mailings, leading to numerous divorces.

*     Allow the warehouse to start small and evolve--Some projects fail by defining too broad of a scope for the project. Successful projects consider their first effort as a prototype and continue to evolve from that point.

*     Ensure intimate end-user involvement--Data warehouses cannot be developed in a vacuum. The system must be flexible to address changing end-user requirements, and the end-users must understand the architecture so they are aware of the limitations of their warehouse.

*     Properly plan the infrastructure--A new infrastructure must be designed to handle communications among data sources. Parallel computers must be evaluated and installed, and staff must be appropriately educated.

*     Perform proper data modeling and stress testing--The data model must be validated and stress tested so that the finished system performs at acceptable levels. A model that works great at 10 GB may not function as the warehouse grows to 100 GB.

*     Choose the right tools--Many projects are led astray because of vendor hype. Unfortunately, many vendors inappropriately label their products as ?warehouse? applications, or they exaggerate the functionality of their tools.

Basic Project Management

As a general definition, a project is any set of tasks with a specific objective to be completed within certain specifications (including defined start and end dates) that consumes capital resources. Given this simplistic definition of a project, let?s define what project management is and how it applies to a data warehouse project.

For every large data warehouse project, traditional management must be replaced by a new type of management that is temporary and very flexible, with a fast reaction time, and able to respond rapidly to both internal and external changes. With this type of management in place, data warehouse project management encompasses the following activities:

*     Defining work requirements

*     Defining the quantity of work

*     Defining the resources needed

*     Monitoring the project by:

      *     Tracking progress (dates and milestones)

      *     Comparing actual figures to predicted figures

      *     Analyzing the impact of changes

      *     Making adjustments to the project

While these tasks may seem mundane, effective project management is critical to the success of a data warehouse. Successful project management is defined as meeting the objectives of a project within project and cost constraints, while maintaining a desired level of performance and fully utilizing the proper technology.

To effectively fulfill the project management functions listed previously, data warehouse project managers must be able to:

*     Identify function responsibilities and ensure that all activities are accounted for.

*     Minimize the need for continuous reporting.

*     Identify the time limits for scheduling.

*     Identify a methodology for tradeoff analysis (shifting resources).

*     Measure the project accomplishments against the plans.

*     Identify and resolve problems quickly.

*     Improve estimation capabilities for future planning.

*     Keep track of meeting project objectives.

Data warehouse project management is different from traditional management in several ways. First, while the evolution of data warehouse queries may be perpetual, the initial creation of the warehouse is a finite activity, and the project manager must be able to deal with this temporary authority because other managers are performing the staffing functions, supplying members of the data warehouse team. To further confound matters, the data warehouse project manager does not have direct control over the financial resources.

Effective Project Management

In general, there are two levels of project management: top-level project management, which controls the overall warehouse project, and functional management, which incorporates everyone involved in the operational details associated with each specific milestone of the project.

The size of a warehouse project does not really impact how the project is modeled and controlled. While there are numerous tools, such as PERT (Project Evaluation and Review Technique), that can be used for very large data warehouse projects, all warehouse projects are fundamentally the same; the only variables are the number of sub-projects and the complexity of integrating the sub-projects.

A very large warehouse project, such as building an enterprise-wide data model for a large corporation, may involve thousands of milestones and man-centuries of effort, but they still maintain the fundamental nature of a warehouse project. The issues are purely a matter of scale. However, it is comforting to see that a data warehouse project, even with a man-century of effort, is relatively small when compared to other projects such as building an aircraft carrier which could consume the full-time efforts of  thousands of people for several years. The term ?man-century? refers to 100 years of labor, and is equivalent to 100 people working full-time for a year.  Table 2.3 shows three levels of project size. As you can see, a data warehouse project is generally classified as a medium-size project.

Project Size

Number of Tasks

Project Duration










Table 2.3  Levels of project size.

The management of an organization must not underestimate the importance of effective project management, and effective project management includes troubleshooting. Troubleshooting usually involves at least one of the following three categories:

*     High Costs--Cost overruns stemming primarily from improper allocation of human resources.

*     Project Delays?Project delays are often a result of wasted resources (i.e., materials, people and so forth), which can cause the premature or late delivery of project resources.

*     Poor Quality--Poor quality occurs when a project does not meet performance or functionality objectives.

In any case, special care must be taken to ensure that project management avoids as many unforeseen problems as possible. One of the best ways to ensure that a data warehouse project is created soundly is for the warehouse team to prepare a complete  description of the project, clearly stating all project requirements and expectations up front. This description is called a scope of work agreement.


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