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Global Demographics – Capability variations and age variations

Global Demographics – Capability variations and age variations

Edited by K. Anne-Rivers Forcke, IBM Human Ability and Accessibility Center.
Contributors: James Thurston, Microsoft Trustworthy Computing Group; Martin Gould, Accessibility Expert; Andi Snow-Weaver, IBM
Human Ability and Accessibility Center; Susan Schorr, Head, Special Initiatives Division, ITU Telecommunication Development Bureau (BDT)

Section Summary
The World Bank in its 2007 report estimated the number of persons with disabilities to be between 10-12% of the global population (691-829 million people), and the figure is expected to reach one billion (915 million – 1.1 billion) as we approach the midpoint of the 21st century.

The fact that human capability varies continuously throughout a lifetime is responsible for much of the complexity in ICT accessibility, and is a fact that must be considered by policymakers and engineers when coming up with standards. The Inclusive Design Toolkit framework refers to seven user capabilities which can be used in this context:
-    Sensory: vision and hearing
-    Cognitive: thinking and communication
-    Motor: locomotion, reach and stretch, dexterity.
There is also a variation with age that needs to be considered; policy makers need to keep in mind that an increasing percentage of population is going to be dependent on others with old age, and accessibility solutions need to cater to their needs as well. These variations have an implications for the productivity of nations, and the section discusses how such productivity can be increased.

$220 billion: The annual disposable income of persons with disabilities Latest Disability Stats

The “medical model of disability” – the model most widely understood and interpreted today – considers disability “a physical, mental, or psychological condition that limits a person’s activities,” linked to various medical conditions and viewed as a problem residing within the affected individual.

Considering this model of disability, along with statistics reported in both developed and developing countries, the World Bank in its 2007 report “Measuring Disability Prevalence” estimated the number persons with disabilities to be between 10-12% of the global population. Based on this and the United Nation’s World Population Prospects 2008, which indicates a global population of slightly more than 6.9 billion people in 2010, Table 2.3.1 shows the estimated global population of persons with disabilities reaching just under a billion people (691-829 million people) within the next year, and expected to exceed 1 billion (915 million – 1.1 billion) as we approach the midpoint of the 21st century. 







Medium variant






Estimates of global population of persons with disabilities

(imputed as 10-12%, in millions)






Table 2.3.1  


According to the International Telecommunication Union (ITU), as of 2007 there were slightly fewer than 6.3 billion people living within the 139 countries which have currently signed the UNCPRD (April 2009). These 6 billion people represent slightly more than 89% of the global population. Relying once again on the World Bank estimates of the number persons with disabilities to be between 10-12% of the global population, Table 2.3.2 shows that we are reasonable to estimate that between 603-756 million persons with disabilities are today living in countries with a political commitment to ensuring ICT accessibility.



Current population of UNCPRD Signatory Countries [1]
(in billions)


Estimates of global persons with disabilities population affected by country commitments to UNCPRD 

(imputed as 10-12%, in millions)


Table 2.3.2

[1] ITU database, population series, 2009.

Historically, people have been viewed as being either able-bodied or disabled. Today, we still tend to view persons as belonging to one of the other of these two categories when we know – in fact – that human capability varies continuously throughout a lifetime. The i~design2 Team who is responsible for the development of the Inclusive Design Toolkit refers to this as human “capability variations.” 

Capability variations
To gain a deeper understanding of the variance of human capabilities and how ICT products (or any products) function relative to the range in abilities of an end-user, it is helpful to refer once again to the work done by this team. The Inclusive Design Toolkit provides a framework for relating data regarding user capabilities to descriptions of products and their interfaces. The framework acts as an introduction to descriptions of the seven user capabilities which are grouped into three categories: 1) “sensory” which includes vision and hearing; 2) “cognitive” which includes thinking and communication; and 3) “motor” which include locomotion, reach and stretch, and dexterity. Each of these seven capabilities is important to understand relevant to a person’s interaction with their environment since many medical conditions can affect these capabilities. In general, most people experience more than one capability loss throughout their lifetime usually in the form of multiple minor impairments (e.g., decreased in vision, hearing or dexterity) as opposed to a single major capability loss such as blindness, deafness or paraplegia. This pattern of multiple minor impairments over time is typical of the human aging process.  

The fact that human capability varies continuously throughout a lifetime is responsible for much of the complexity in ICT accessibility. It is also perhaps one of the most consistent forces underscoring the global imperative for thorough consideration, clarity and harmonization in developing ICT accessibility standards as well as technology policies. Years of global research have helped subject matter experts like the Disability and Development team at the World Bank to develop heuristic methods for estimating the number of persons with medical disabilities in any given population. Likewise, policymakers can reflect on the many years of national and international research, debate, standards development and policy formulation from around the world for the heuristic methods supporting unambiguous technical standards and policies that enable both consumers and producers to recognize the benefits of an accessible ICT products and services.

Age variations
In addition to considering capability variations of a population, “age variation” within a population is as much as consideration for policymakers as it is for product and service designers. The World Health Organization (WHO) pointed out in 2005 that increased life expectancy in industrial countries will contribute to the increase in the number of persons with disabilities worldwide.

While our estimate of the world’s population of persons with disabilities seems a relatively constant percentage (10-12%), the increase in the rate of growth of the over-65 population is expected to more than double over the next 40 years, climbing from 7% to 16% or nearly 1.5 billion people globally, according to the UN‘s World Populations Prospects (2008 revision) and as shown in Table 2.3.3:








World Population

aged 65+ 

(in millions)

medium variant







World Population    (in millions)

medium variant







 Table 2.3.3


This aging population is significant in both its number and its implications for ICT policy as well as device and software development. Persons are likely to develop new difficulties and impairments as they age – whether it is sensory (vision and hearing), cognitive (thinking and communication) or motor (locomotion, reach and stretch, and dexterity). Likewise, persons with existing mild difficulties and impairments may experience an increase in the severity of impairment. In any population in which the age profile is shifting to reflect an increasing number of older people, the total number of persons with difficulties and impairments will increase thus exacerbating the need for accessible technology. Simply put, the increased age of the population creates an immediate “second tier” of demand for accessible ICT in the form of older persons experiencing diminished sensory, motor, or cognitive capabilities. 

In particular, the demographics of the developed economies are changing, with longer life expectancies and a reduced birth rate resulting in an increased proportion of people over 65 in the population. As we see in Figure 2.3.4 from the UN Programme on Ageing, the percentage of the population over age 65 is expected to triple for the regions of Asia and Latin American and the Caribbean between 2005 and 2050. Likewise, this segment of the population will double or early double in all other regions of the world (Africa, Europe, Northern America and Oceania) during the same period.   

Some of the impacts of the aging population in the U.S. are explored in a study commissioned by Microsoft in 2003. In this study the data that shows that most of the increase in severe difficulties and impairments occurs among persons in their 60s and early 70s, as shown in Figure 2.3.5. The study, conducted by Forrester Research, found that more than a third of persons in the United States are 65 years and older, and have severe difficulties and impairments.

Further, Forrester found that as the U.S. population ages, more U.S. workers and computer users will notice changes in their abilities and experience difficulties and impairments. It is also predicted that U.S. workers will remain in the workforce long past previously expected retirement ages, making productivity among U.S. workers—regardless of abilities, difficulties, and impairments—an increasingly vital economic issue for U.S. businesses.
More so than previous generations, workers currently age 55-64 are more likely to use computers at work. However, beyond the workplace, there is not only an increase in the use of computers for information and communication, but also an overall increase in the average age of computer users in the U.S. As these current 55- to 64-year-olds mature into their 60s and 70s, they are likely to continue to use computers, with the predicted results being that in 10 years, there will be 2.5 times as many adults who range from 65 to 74 years old using computers as there are today.

Based on these trends, Forrester asserted that it is clear that future computer users will demand and expect greater accessibility in computers—regardless of their abilities, concluding that “The need for accessible technology is great now and will intensify over the next decade.”

While the Forrester study clearly demonstrates the increasing need for accessible ICT in the workplace due to the aging workforce, there is a need to look beyond the microeconomic focus on the firm and consider a how accessible ICT might help address a broader, macroeconomic effect of an aging population; the need for increased productivity within the smaller working population.

The steadily increasing population of persons over the age of 65 brings with it a reduction in the Potential Support Ratio (PSR). The PSR is the number of persons age 15-64 in the population per one person aged 65 or older in the population. In 1950 the worldwide PSR was 12:1; in 2000 the PSR was 9:1; by 2050 it is expected to be 4:1 globally and a mere 2:1 in the developed world. More information on the PSR can be found and its implications for product design can be found in the Inclusive Design Toolkit.

The United Nation’s Programme on Ageing employs a slightly different approach, referring instead to the “old-age dependency ratio” (ODR) the number of people aged 65 or older in the population per one person aged 15-64 (working age) in the population.

Figure 2.3.6 shows these dependency ratios for the various economies (figure coming soon).

Consistent with the demographic data showing the increasing age of the populations in high income/more developed economies, we can see in Figure 2.3.6 that it is the more developed economies that are facing the highest old-age dependency ratios. It is estimated that the developed economies will be facing dependency rations of 45:1 by 2050. In other words, the population of these countries will be composed of 45 old-age dependents per one person of workforce age by 2050. In short, these economies will see the ratio of old-age dependents more than double within these 50 years. 

For those familiar with the social and demographic trends in more developed regions, this is not surprising.  However, what might be more of a surprise is what we see in Figure 2.3.6. Using population data from the UN’s World Population Prospects, we can see that the less developed regions (not including the least developed countries) are projected to have the steepest growth in their old-age dependency ratios over the next 40 years. These regions are predicted to experience 200% increase in the ratio of people over 65 to those of workforce age (age 15-64) between 2000 and 2050 as compared to the slightly more than a 100% increase predicted for the more developed regions and slightly less than a 100% increase in the ratio of people over 65 to those of workforce age in the least developed countries.   

With an increasing dependency ratio comes an increasing requirement for workforce productivity. While this seems logical – even intuitive – using empirical methods to examine labor productivity can actually help us more accurately demonstrate just how accessible ICT can benefit a national economy.

Productivity for firms and nations
The primary resource to consider when we begin to examine the relationship between 1) accessible ICT and assistive technologies, 2) employee productivity and 3) the economic output of firms and nations is Adam Smith’s indispensable An Inquiry into the Nature and Causes of the Wealth of Nations. Also helpful is Dr. Seppo Saari’s Productivity: Theory and Measurement in Business. From these two sources, we know that in a national economy, the total production is measured as the sum of value added and the production function of national economy is written as follows:

                                                               Output = f (Capital, Labor)
Here “Capital” describes human-made goods such as machinery and equipment and “Labor” describes human effort used in production, including expertise. This helps us to see quite quickly that – holding capital constant – a decrease in labor will result in a decrease in national output.

Similarly, at the firm level, we know that the factors (inputs) of production are 1) land 2) labor and 3) capital and can be written as follows:

Output = f (Land, Labor, Capital)

As with the national economy model, a decrease in the quantity of labor at the firm level - holding constant the amount of land and capital – will result in a decrease of the firm’s overall production (output).

We can also look at production (output) as a function of productivity. Productivity in economics is the ratio of what is produced to what is required to produce and the formula of total productivity is normally written as follows:

 Total productivity = Output quantity / Input quantity

From either the firm perspective or the national perspective, then, we can look at productivity relative to production (output) as follows:
                                           Output quantity = input quantity x total productivity

Translated for the firm, then, this can be written as:

                 Output quantity = quantity (land, labor, capital) x total productivity

And for the national economy, it is written:

Output quantity = quantity (labor, capital) x total productivity

In both equations, we can clearly observe the role that the quantity of labor plays in the output of the firm or the nation. If there is an expectation for firms and national economies to maintain or even increase their current levels of production (output) each year, yet they are faced with a decreasing quantity of the labor factor, such as the one currently facing many of the high-income countries, then these firms and economies must increase their supply of capital and/ or their total productivity just to maintain their current levels of production. 

Increasing productivity
Firms can increase productivity in a variety of ways. Saari points out that some of the most obvious methods involve automation and computerization. Recently, however, less obvious techniques are being employed that involve ergonomic design and worker comfort. A comfortable employee, the theory maintains, can produce more than a counterpart who struggles through the day. 
It is here where we see the particular role for accessible ICT to act as a direct, positive force helping to increase employee productivity. By removing barriers to using automation and computerization (both of which are capital inputs into production) and enabling a more comfortable workplace, accessible information and communication technologies can help to create a more productive workplace for a more diverse workforce.

As we have just seen, increased productivity at the firm level contributes to increased productivity at the national economic level. And this is especially significant in economies where there is an increasing proportion of the population reliant upon the productivity of a decreasing proportion of the population.

Looking,then, solely through the lens of the medical model of disability, and considering almost exclusively the global populations of persons with disabilities, plus those people aged 65 years and older and likely to have or develop a medical disability, there is today an estimated market force of more than one billion people worldwide who require that the information and communication technology be accessible.

Perhaps even more importantly, and as we look to the future, we now recognize that there are multiple dimensions of people who benefit from accessible ICT. As we have already noted, the direct and primary beneficiaries are the more than 1 billion people worldwide with disabilities or diminished capabilities for whom accessible ICT contributes to an improvement in their overall quality of life. However, it is perhaps equally important for policymakers to recognize and consider that the businesses, communities and economies which depend on the productivity and contributions of these two constituencies represent a second dimension of direct beneficiaries of accessible ICT. 

Helpful tools and links about population demographics
1. United Nations World Population Prospects (2012)  
2. United States Census Bureau
3. The Inclusive Design Toolkit
4. The Market for Accessible Technologies