Dual-Platform Support Costs

Following is the summary of the Gartner Group report titled

Technical Support Costs and Dual-Platform Desktops:
Managed Diversity

Gartner Group Consulting Services recently concluded an extensive survey of actual dual-platform costs collected from real organizations in the US. Conventional wisdom indicates that it costs more to support both Macintosh and Windows than to support Windows alone. In their report titled "Technical Support Costs and Dual-Platform Desktops: Managed Diversity," (copyright 1995 by Gartner Group) Gartner Group concludes there is no support cost premium associated with having both Macintosh and Windows (that is, heterogeneous computing) over being single platform (homogeneous computing).

Official Reprints Available

The report is available in the US by calling 1-800-232-9335.

Objectives of the Study

Gartner Group Consulting Services examines IT technical support costs in medium to large organizations. The key objective of this study was to quantify the effect on technical support costs of heterogeneity in end user computing environments. The study sample size exceeded 312,000 desktop computers. The study aimed at providing answers to the following questions:

In this study, Gartner Group surveyed over 65 enterprise IT organizations in the US in mid 1995, evaluating existing technical support infrastructure and costs. The study covered over 312,000 desktop computers. As such, the study includes varying mixes of Macintosh (up to and including Mac OS version 7.5.1) and Windows based desktops (up to and including Microsoft version 3.11). The study was concluded while Windows 95 was still in beta test. Gartner Group says that while Windows 95 has minimally lower support costs than does Windows 3.x, there is nothing about Windows 95 that changes the fundamental conclusions of their study.


Most organizations deploy desktop computers from several hardware vendors, supporting both Macintosh and Windows. Gartner Group calls this "heterogeneous computing" because there is so much diversity apparent at the desktop.

At the same time, IT organizations are often under budget pressure and are called on to reduce the costs of supporting the overall organization without regard to any benefits of dual-platforms to end users. This has led some IT organizations to evaluate the single platform challenge: would an all-Windows environment have lower IT technical support costs than a dual platform one?

The common wisdom is that initial installations of a technology bear a larger portion of the support costs and, as the technology proliferates, support costs can be spread over a larger installed base, lowering the incremental support cost of later units. Old erroneous beliefs were that introduction of a second technology will dilute this economy of scale and unavoidably make a dual-platform environment more expensive to support. Furthermore, this effect will be present even if one of the technologies has fundamentally lower support costs than the other.

Following is a "theoretical" model of what such a dual-platform penalty region would look like. At one extreme is all Windows; at the other is all Macintosh. In the middle, the "hump," if it exists, would represent the extra costs of being dual platform. Note that Gartner Group did not find any such region in the data.

[Theoretical Model]

Effect of Windows 95

Gartner Group's major conclusion is that, while conventional wisdom might suggest that standardization on a single platform would lower technical support expenses, there is no cost premium associated with supporting both Macintosh and Windows. And, while the study was conducted prior to the public release of Windows 95, Gartner Group says that deployment of Windows 95 doesn't change the fundamental conclusions of this study.

Gartner Group's Methodology

The principal methodology used was a survey conducted using one-to-one audio teleconferencing interviews. Sixty-seven companies, all located in North America, participated in the survey; the sample size exceeded 312,000 desktop computers. The companies represented a wide range of industry sectors, installed base sizes, and degrees of heterogeneity. The survey was supplemented by a small number of audio teleconferences that were held with a subset of the participant companies.

The data were gathered in mid-1995 and were not supplemented by data collected during previous studies. Although a certain amount of filtering had to be performed to eliminate responses that were incomplete, no attempt was made to infer or reconstruct missing data. Technical support costs were equated with full-time equivalent (FTE) technical support personnel. Gartner Group has often found that personnel costs are the main determinant of technical support costs, and furthermore, that it is usually quantifiable more accurately than other cost elements. A number of different data analysis methods were used to analyze the data, to accommodate the nonlinearity of some of the data.

Effect of Diversity on Support Costs

Gartner Group found that total technical support costs in 90% of the enterprises surveyed fall below 0.025 FTEs/end user desktop. The most remarkable feature of these data is that they do not show any deviation from linearity: there is no "dual-platform penalty" region wherein the technical support costs are driven upward. Gartner Group concludes from this that dual platform desktop standards (Macintosh and Windows) do not lead to detectable increases in technical support costs.

[Graph of Effect of Diversity on
Technical Support Costs]

Regression lines fit through the data tend downward to the right (100% Macintosh). This confirms the frequently reported fact that Macintoshes are less expensive to support than Windows systems (25% less in this study) and Gartner Group concludes that overall support costs decline as the percentage of Macintosh systems in the environment increases.

Effect of Support Quality

To investigate whether the differences between Windows and Macintosh costs were due to differences in the quality of technical support, Gartner Group conducted a pairwise comparison between Windows and Macintosh support costs in individual enterprises. Gartner Group found that in most environments, and regardless of the degree of Macintosh penetration, the Macintosh was less expensive to support than Windows. Again, there is no visible effect due to mixing desktop platforms.

A closer look at those few environments in which Macintosh technical support costs exceed those for Windows reveals some of the critical cost drivers. The use of problem resolution tools, for example, reduces Macintosh support costs, as does the integration of these tools with network management tools. Also, the use of multiple versions of the Macintosh operating system also increases support costs.

Effect of Management Style

There are some environments that apparently do not have the same level of management control as others. Gartner Group believes that these different environments, which they characterize as tightly managed and loosely managed, are responsible for the existence of two distinct bands in the support cost data, separated by a factor of four, into which the data cluster. After separating the data into these two groups, Gartner Group found that one average technical support person can care for about 95 Macintoshes or 77 Windows systems in tightly managed environments. These ratios drop to 23 and 18, respectively, in loosely managed situations.

Average number of end users supported by one technical support person:

                   Tightly Managed             Loosely Managed
                   Environments *              Environments *
                   ___________________         ________________________
 Macintosh :
 platform  :       95 end users                23 end users
 Windows   :
 platform  :       77 end users                18 end users
* Not all environments experience the same level of management control. Some are more successful than others at controlling technical support costs. Gartner Group refers to these as "tightly managed" environments.

Best Use of Existing Windows Computers

Gartner Group also found that increased production-type use (e.g., terminal emulation) decreases support costs. This effect is particularly marked in the case of the Windows systems, where, increasing terminal emulation usage from 0% to 100% can reduce support costs by 50%. Gartner concludes that concentrating existing Windows systems in production-type use will reduce technical support costs.

Effect of Remote Backup

In a similar vein, Gartner Group found that sites with higher levels of remote backup incur higher technical support costs. But this increase could be due as much to the fact that the labor associated with local backups may be drawn from the end user community itself and therefore not recorded in the study as would centrally managed technical support. It is also possible, of course, that if backups are not done remotely, with the help of formal technical support staff, they don't get done at all.

Effect of End-User Training

One way to assess the validity of the unexpected results of this study is to see if the same data can be used to confirm other, more familiar, observations. For example, and in agreement with other studies, Gartner Group found that while organizations that provide less than three days of end user training per year frequently experience larger support costs, those that provide more than three days per year see no further reduction in costs.

[Effect of End User Training on Support

The survey data collected in this study do not allow assignment of cause and effect. As an example, the data are clear that no installation with more than about 5,000 units falls into the loosely managed category. But is it the case that having more desktops reduces technical support costs? It could just as readily be argued that unless tight management is practiced, organizations are unable to grow to over 5,000 desktops. The data by themselves do not suggest either one interpretation or the other.

Standardize at the Network and Application Layers

Most of Gartner Group's interviewees agreed that successful control of support costs was made possible by managing diversity at two crucial architectural layers: networking (file and print services) and applications. Although the benefits to be achieved by the flexible use of multiple desktop systems have long been felt, it was always believed that the costs of supporting such environments made their use impractical. Gartner Group's observations indicate that a significant number of enterprises have learned where to concentrate their management efforts: it appears that they have learned to "manage their way out" of the extra costs that have long been thought to result from such arrangements. Whereas in the past, it was thought that to control these extra costs one should manage at the hardware on OS layers (that is, go single platform), in this study Gartner Group found the companies would have success managing at the network and application layers.

[Architectural model]

Windows Systems Inherently More Heterogeneous

Finally, Gartner Group concluded that in the real world, there really is no such thing as being "single platform." Companies deploy multiple generations of Windows platforms from several different hardware vendors. Thus, even in the "pure" Windows shop, there are multiple add-in cards both from vendors and from users, differing versions of device drivers, microprocessors generations, differing BIOS, even differing x86 compatible microprocessor vendors. Gartner Group concludes that "every environment is heterogeneous, and Windows environments are more heterogeneous than Macintosh environments."

Gartner Group Findings and Recommendations

Gartner Group's answers to the study objectives are as follows:

In order to reduce technical support costs, Gartner Group recommends the following:

The preceding is a summary of the Gartner Group report titled "Technical Support Costs and Dual-Platform Desktops: Managed Diversity" (copyright 1995 by Gartner Group) presented at the European Mac IS Conference October 1-3, 1995, by Dr. H. Walter Johnson, Vice President, Gartner Group Consulting Services.

Official Reprints Available

The report is available in the US by calling 1-800-232-9335.

Copyright 1995