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 |