Monday, July 25, 2016

Quantifying Your Closet

In this post we will discuss some ways that you can track the eco-friendliness of your wardrobe, which we will collectively refer to as your Sustainability Score. While this is no doubt far from a perfect science, there are a few straightforward statistics that we can use to analysis our apparel decisions.

As we cover each individual Sustainability Score factor, we will reference the following data:

BrandCostPurchase DateWear Count
Nike$110.0004/06/2014‎ 100

Brand Rating (BR)

As discussed in a previous post, there is a website called Rank A Brand that "assesses and ranks consumer brands in several sectors on sustainability and social responsibility." Each brand is ranked on a scale of 0 - 32, with 32 being the most sustainable. We will use these rankings as our first factor.

To find a rating, we go to Rank A Brand's search page and type in our brand's name. This gives us ratings of 10, 5, 11 and 3 -- for an average Brand Rating (ABR) of 7.25. This is definitely on the low side, as we want to get as close to 32 as possible.

Item Age (IA)

The goal of this factor is to avoid a high apparel turnover rate. We do this with the following formula:
IA = [months since purchase] / 6
This rewards us for every 6 months we own an item. In other words, our sustainability score will increase as our average item age increases. For our first item, the calculation is:
841 days / 30.1467 = 27.89 months / 6 = 4.65
Repeating the above calculation for our other items gives us IAs of 4.65, 0.93, 2.04 and 7.78, and a median Item Age (MIA) of 3.33 (note: we use a median instead of a mean to avoid giving too much weight to any particular item).

Cost-Per-Wear (CPW)

This factor is easily the most used and its formula is also quite simple:
CPW = cost / [times worn]
Essentially, it is designed to reward high usage of apparel: every time you wear an item, you decrease its CPW. Using our example data, we get CPWs of $1.10, $12.4, $6.95 and $0.25. This gives a median CPW (MCPW) of $4.03.

Sustainability Score
In our case, we have
SS = (7.25 + 3.33) - 4.03 = 6.55
This is obviously a pretty low score. However, we can improve our score by (1) buying from brands with a high Brand Rating, (2) keeping our apparel for as long as possible and (3) wearing our apparel as often as possible. Obviously, the best way to achieve this is to be selective with what you buy. In other words, it's much easier to meet the above criteria with a small wardrobe than it is with a large one.

What's your Sustainability Score?

(Check back soon to find out how to turn all of this into an easy-to-use spreadsheet!)

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