They will first ask 15 questions which are quite vague and open to interpretation.
http://walmartstores.com/download/3863.pdf

They will then fund a consortium to develop a tool to evaluate the sustainability of a product the Sustainability product Index
http://walmartstores.com/download/3879.pdf

You might notice that in the 15 questions asked to suppliers some issues such as

•    Energy and Climate
•    Natural resources
•    Material efficiency
•    People and Community

are  included but in step 2 – the tool development- some issues are missing, the SPI is created using Life Cycle Assessment.

Walmart has chosen the term sustainable for its index  : the Sustainable Product Index. The term Sustainability can be interpreted in many different ways – a coal mine and an organic veggie patch can both be sustainable – and what Walmart defines as a sustainable product is fine but only to Walmart.
Walmart uses Life Cycle Assessment to assess the sustainability of a product.
This is quite a narrow way to assess the sustainability of a product as it doesn’t take into account social impacts and some environmental impacts are not included in LCAs. If Walmart is really serious about creating an index that can be used by consumers to make choices on environmental and or social grounds then that is not the best tool to use.

The SPI is a good initiative but it has many downfalls:

•    Social impacts are not included
•    Consumers behaviours are not included
•    Behaviours “created” by the SPI
•    Environmental impacts not included in LCAs
•    Reliability of product

Let’s take Coca-Cola as an example. The LCA will have taken into account how much water is necessary to produce a liter of Coke but some of the impacts it won’t take into account are:
•    where the water was taken, whether it is from a water depleted region or not.
•    the working conditions of workers and the social impacts of operating the factory
•    the impacts related to consuming the product – obesity etc..

The rating becomes even more complex with multinationals: you might buy a 5 star product in a country where Walmart is represented but support a company  –by buying the product -that produces the same product at 2 or 3 stars in other countries.
Let’s take Coca-Cola as an example again, they have more than 300 bottling partners in more than 20 countries all with different standards, different logistics and Coke is sold in more than 200 countries whereas Walmart is “only” in 15 countries, how do you calculate an accurate LCA for a product like this one?

3.5 stars  x  temperature in the air / colour of the sky  would be a great formula..

Another flaw is the durability of a product; as an example is a TV at 4 stars that last an average of 20 years better than a 5 stars TV lasting 10 years?
For an answer see formula above.

But my main concern is the SPI itself, the device that people will use to make their choices. Consumer choices and responsibility will be “removed” from consumers to be replaced by a tool funded by Walmart.
This tool defines – in a very narrow way – what a sustainable product is and what 1 billion people/year should consume should they want to consume sustainably. Walmart’s suppliers will also design their product with the SPI in mind and might leave out other environmental or social initiatives.
The SPI is trying to define what a sustainable product is which is a very wide concept encapsulating various issues with a tool that has a narrow focus; a little bit like trying to light a stadium with a lantern, it will be lit – by definition – but only a small chosen area will be lit.  The issue here is that Walmart consumers will think they are consuming sustainably, doing their bit, relying “faithfully” on the SPI to help them choose a sustainable product, whereas in fact they are consuming what Walmart think is sustainable, leaving out very important impacts involved in the production and consumption of a product. This can have great environmental consequences and it threatens our freedom to choose.

I am not against indexes if what they communicate is precise and not misleading:

•    water rating on a washing machine tells you how much water is used
•    energy rating tells you how much electricity is consumed
•    fuel consumption tells you what a car consumes

The SPI is precise but is used in a misleading way, some of the things I would like to see are:

•    renaming the index to what it actually measures, if it measures CO2 then call it CO2 index.
•    communicate to customers what is and isn’t in the index and what is important to consider when buying a product
•    information about what suppliers do in terms of reducing their environmental and social impact at a global level
•    clear and transparent labeling
•    consumer education

The SPI index could become a good tool if it does what the water rating does, giving a simple measurement and clearly says what it measures, we can then with this figure decide in conjunction with other factors if we want to buy a 5 star product from x country with bad social record or a 3 star product from y country with good social record. It might be harder for consumer to make a decision but it will be an informed decision and it will keep Walmart suppliers on their toes because they will have to communicate on what they do socially and environmentally and not hide behind the SPI.