This is a preview of a member exclusive premium article.

Editor’s Introduction

How to buy outdoor gear? How might an intrepid backpacker face all of the confusion? Luckily, there are some tools to navigate the complex waters of choosing what outdoor gear to buy, including functional analysis.

Functional analysis is used to design all kinds of products. Some design engineers claim that it is the cornerstone of all product development. Outdoor gear companies, MYOGers, and others use functional analysis to develop outdoor gear. Jörgen Johansson has discovered that functional analysis is not only for people making equipment. It helps you evaluate the pros and cons of different kinds of stuff you run into at REI or elsewhere. Functional analysis will help you become an expert buyer of gear for your outings. In this article, Jörgen tells you how to go about this.

We recently published How to Choose Lightweight Backpacking Gear: Save Weight, Money, Hassle, and Time which was a high-level explanation of choosing what lightweight backpacking gear you need to complete your adventures. In that article, we recommended first identifying your core needs. What’s the difference between trail running shoes, footwear, and foot protection? Next, we presented the idea that well-designed functional systems can serve your core needs. This article, How to Buy Outdoor Gear – Functional Analysis, dives into more detail about functional systems. Jörgen Johansson wrote this piece to give you the framework and tools to identify what you need and what system(s) will help you meet this need.

We recommend reading How to Choose Lightweight Backpacking Gear: Save Weight, Money, Hassle, and Time first as it forms an excellent foundation for this more detailed article which jumps specifically into how functional analysis can be used to make more informed and thoughtful gear purchasing decisions.

– Eric Vann, Associate Editor

Structure Your Buying Decisions

In this article, I may use the expressions “gear for your outings” and not “outdoor gear.” This signals that keeping an open mind and realizing that a lot of things designed for purposes other than outings might be an option. They might even work better than “outdoor gear” or “backpacking gear” that outdoor specialty stores sell. Using grease pots from Walmart for cooking and running clothes for backpacking comes to mind.

Functional analysis is a structured way of forcing you to keep an open mind. For example, functional analysis forces you not to jump to conclusions, like: “I need a pair of backpacking pants,” and instead provides a framework for asking the question “Why do I need a pair of backpacking pants?”

Now, structured ways of doing things can often be 80 percent “common sense” or “why that is obvious.” Still, functional analysis can be useful because it might help us not to overlook the other 20 percent. So, please bear with me as I walk you through this presentation of functional analysis. I think it will turn out useful in the end because it might help you realize that what you need is a pair of runner’s pants for backpacking!

Maybe I should also mention that I am by no means a design engineer. Luckily, my design engineer friends help me along. So what I am writing here is my attempt to translate what the experts are talking about. Translate it into something that I, as an amateur, can understand but also can use when it comes to choosing outdoor gear.

Drying Gear, John Muir Trail, How to Buy Outdoor Gear, Functional Analysis, Jorgen Johansson
Lots of gear on display, or rather, to dry out along the John Muir Trail.

Core or Primary Function

When a product is designed it is important to consider why this thing should exist, its reason for being, the main purpose or main function of it, and how to execute the main objective.

Let us start with a pencil. We might say that its primary objective is to draw a lead line. Unfortunately, this means that we have already made three mistakes.

Number one: it is not the pencil that draws the line, it is the user of the pencil. Secondly, it is unnecessary to limit ourselves by deciding it is supposed to be lead. And thirdly, the pencil is not making the line; the line is becoming manifest when the pencil moves across, for instance, paper.

Now, you might say that I am a hardcore stickler, but these details can be critical in design work. They are also important to understand when you are trying to decide what piece of gear is the best to buy for the purpose you have in mind.

IKEA Pencil, How to Buy Outdoor Gear, Functional Analysis, Jorgen Johansson
Even if the pencil is only an example, I will not refrain from singing its praise. I never understood the idea of bringing ball point pens or mechanical pencils into the backwoods. There is nothing that can go wrong with a pencil in any weather that cannot be fixed by sharpening it with a knife. The short pencils at IKEA warehouses are just long enough to be useful and short enough so they don’t break in the pack.

If you work for a pen factory it might be correct to limit the analysis to pens using ink. But generally, it is best to keep a very open mind, to discover some not so obvious but maybe brilliant solutions. This, by the way, is also a good recipe for most things in life. You can thank me later.

I would venture to formulate the following purpose for our pencil example: “leave a mark” or “make a mark.” This describes the use of the pencil, without unnecessary limitations. It is important to be aware that this purpose manifests itself in many ways: there is not a single, right answer. But a group working on developing a product must, of course, be in agreement here. This purpose is what we from now on will call the core function of this pencil.

Subordinate Functions

So then, how is this essential function of “making a mark” achieved? Pondering the pencil, we realize that the user needs to be able to hold it to make any marks with it. The pencil also has to make a mark of a certain quantity and for a length of time. Quantity is about how wide a mark. For a length of time, in the case of a pencil, you sharpen it. All this supports the core function of “making a mark.” Functions like these that cooperate to deliver a key function are called subordinate functions or sub-functions.

If you cannot grip the pencil and if it does not provide its mark for as long as you need, the core function disappears. So if a sub-function disappears, we also lose the essential function. This is imperative, and a significant difference from the next step in the hierarchy.

Supporting Functions

Looking at a pencil, we notice that it has a brand name printed on it. There is also something indicating the measure of lead hardness. These are called supporting functions. They are supporting one or several features that are above them in a hierarchy, but they are not necessary for the superior function to work. The pencil leaves its mark just as well without the brand name. The brand name is perhaps supporting another function that could be called give status or more simply show brand, but not the primary function of leaving a mark.

How to Name a Function

A very pedagogical way of naming a function is to use an “active verb” describing the process at work, followed by a noun upon which to act. Like I have used “make a mark” or “leave a mark” in the pencil example.

Useful verbs for this are: carry, deliver, make, hide, offer, stop, give, hold, contain, control, admit, regulate, govern and so on.

Nouns could be words like acceleration, balance, torque, energy, grip, interest, instruction, load, mark, abrasion, person, cover, comfort, support, etc.

Function Tree, How to Buy Outdoor Gear, Functional Analysis, Jorgen Johansson
Part of Function tree. Dotted lines usually connect supportive functions, signifying that they are not essential. Going upwards in the hierarchy answers why something should be performed and going downwards answers how to perform something.

Function Tree

This hierarchy of features that I have described can be drawn as a tree. This is often very useful. The idea is that if you move in this tree, away from the core function, this will answer the question “How.” If you climb the tree towards the essential role, this answers the question “Why.” In a tree like this, the lines to sub-functions are solid lines, the ones towards supporting services are dotted. That way it is easier to see what is necessary for the core function and what is not required, but somehow adds value.

Function limit

“Allow grip” is a sub-function of the pencil, as we have seen. But it is not very precise. What is a “grip?” Do you use the entire hand or is it a precision grip using only a few fingers? What is the exact diameter of the pencil supposed to be? There is also a question of friction. How slippery or non-slippery must the pencil be to allow a comfortable grip that can be maintained for as long as necessary. All these are function limits that are usually put in hard numbers or sometimes sufficiently distinct adjectives (“non-slippery”).

Shoe Display, How to Buy Outdoor Gear, Functional Analysis, Jorgen Johansson
Is there any difference between these shoes, except color? Probably. Can these differences be identified as subordinate functions? Probably.


No matter how rigorously we analyze functions when building or evaluating a product, we might end up with contradictory feature limits or sub-functions: both necessary, but in conflict. Often we solve this by prioritizing certain functions or adjusting function limits. This is certainly often the case when evaluating outdoor gear from a weight-conscious perspective. This is the case for most Backpacking Light readers, and this leads us to some practical examples.

The Market for Outdoor Gear

Let us start by stating that the market for outdoor gear is a multinational, billion dollar industry. This might sound like a meaningless banality, but it is important to consider when we are choosing gear for our outdoor ventures.

There are a lot of people out there who want to sell us things. There is nothing wrong with that; it is their job. Our job is to buy what is best for our purposes. It is a slight oversimplification, but they will sell more if we carry 60 pounds (27.2 kg) on our back than if we carry 20 pounds (9.1 kg).

I would also venture to say that we are the only ones in the whole wide world that benefit from a light load. Nobody who is not going to carry your pack is motivated to help you lower your pack weight (except for those of us here at BPL; we need you to remain enthusiastic about carrying a light pack so we can keep educating the masses about the benefits of lightweight wilderness travel!).

Sales staff, National Park staff, outdoor magazines, they all have an ax to grind – convincing you that the equipment you have is inadequate regarding quantity or function. Even if they do not make an actual buck from convincing you to add to your load, they do not want to be accused of putting you in jeopardy by bringing too few or too fragile things, should something happen. So, they are all in the better-safe-than-sorry-league and thus, so often are your friends and family.

So, you are alone against the dark forces. But do not fear. You have functional analysis to guide you through the valley of shadows!

Bridge Over Creek, Yosemite, California, How to Buy Outdoor Gear, Functional Analysis, Jorgen Johansson
Walking through the valley of shadows is not too bad, especially if you have a trail to guide you and a bridge over troubled water. Yosemite, California.

Mature Market

Most outdoor gear sells in what is often called a mature market. Meaning that there are few new products that offer hitherto unknown benefits (gasp!). In other words, there are few products with an entirely new core function (but the marketing materials say otherwise!).

This means that the outdoor industry cannot sell on core function only (few industries can). And as consumers, we certainly encourage this. Faced with two packs that seem to have the same specs for carrying our load, we pick the one we think looks best (unless we belong to an anti-group where we win status from having the ugliest looking pack). Or we choose the brand that we consider “market leader,” or the ones recommended by bloggers online. No matter, we easily become victims to things leading us away from the primary function of a particular piece of gear.

All of the temptations mentioned above are supportive functions and they tend to dominate in a mature market. Of course, core functions exist and subsidiary ones as well. However, very often what differentiates one product from another and makes us buy it, is something that has no (or minuscule) impact on how the product delivers its core function.

Jungle, Mature Marketplace, How to Buy Outdoor Gear, Functional Analysis, Jorgen Johansson
The usual jungle in the mature marketplace. Is there a way through all this?

As consumers, we are so immersed in this that it is often quite difficult to buy gear that suits our purposes appropriately. That is why some get stuck with 8-pound (3.6-kg) packs, 10-pound (4.5-kg) tents, and a hernia. It is difficult to separate what we need from what is nice to have, and we do not always question the cost for all of the nice-to-haves. Money is an important value, but weight costs discomfort, pain, and suffering.

Designers use functional analysis to create useful products that sell well. Consumers can use the same analytical procedure to ensure that we buy what we need, and nothing more.

Rain Jacket – a Practical Example

--- End of free preview ---
Member Exclusive

A Premium or Unlimited Membership* is required to view the rest of this article.


* A Basic Membership is required to view Member Q&A events