Table 1

Independent variables explored for each model

Model

Variable Name [Source/Justification]

Variable Description

Source

Expected Influence ceteris paribus


All

GDP (PPP) [16]

Gross Domestic Product measured in international dollars

WHO

Prices increases with GDP

GDP (USD) [16]

Gross Domestic Product measured in US dollars

WHO

Prices increases with GDP

Both Media Models

Regional Dummies (WHO)

Global Burden of Disease regions (geographic and economic)

WHO

Proximate groups may have similar market structures

Regional Dummies (WB)

World Bank regions – Income groups (economic)

WB

Proximate groups may have similar market structures

Printed Media

Flyer Dummy

Variable indicating if price is for flyer rather than poster

Collected data/WHO

Lower price if flyer

Flyer Dummy * GDP

Interaction term

Price of flyers may have different relation to GDP than posters if different printing technologies are used

Advertising Media

Population in service area [17]

Total population in area reached by a media outlet

UN Stats/World Gazetteer

Larger population raises price

Predicted market size [17]

Total population in area reached by a media outlet adjusted for access to media outlets

UN Stats

Larger population raises price

Competition within media outlet type [23;24;25]

Number of media outlets within a category (TV, Radio, Newspaper), adjusted and unadjusted for predicted market size

CIA Fact book/UN Stats

Greater competition would likely reduce prices (although interacts with demand for media)

Competition with all media outlet types [23]

Number of media outlets across categories (TV, Radio, Newspaper), adjusted and unadjusted for predicted market size

Monopoly [17]

Collected data

Monopoly would likely raise prices

Government Ownership [17]

Undetermined; depends on government pricing policy but likely would raise prices if monopoly or lower prices if in competitive market.

Newspaper Dummy

Variable indicating if price is for Newspaper rather than radio

Collected data/WHO

Higher price than radio

TV Dummy

Variable indicating if price is for TV rather than radio

Higher price than radio

Dummies * GDP

Interaction term

Price of media may have different relation to GDP than radio because different technologies are used

Water

Access to fresh water

Amount of water available per capita (annual)

WB Development Indicators

Higher access to water should lower price

Total quantity of water supplied [17;33]

Total amount of water supplied in a country (annual)

More demand should raise prices; may also indicate dis/economies of scale

Island (dummy)

Variable indicates if the country is a small island

Data collected

Increase price if an island

Annual Rainfall [33]

Total annual rainfall

Country Watch

Increased rainfall should decrease price of water

Electricity

Fraction derived from fossil fuels

Percentage of electricity generated from fossil fuels

CIA Fact book

Higher fossil fuel use should increases price

Fraction imported

Percentage of electricity consumed that is imported

Higher imports should increase price

Total electricity consumption [17]

Total amount of electricity consumed

More demand should raise prices; may also indicate dis/economies of scale

Total electricity production [17]

Total amount of electricity produced


Johns et al. Cost Effectiveness and Resource Allocation 2006 4:8   doi:10.1186/1478-7547-4-8

Open Data