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Why Duffel Helps You Find Your Routes.

Profile image of post author Adam Lancaster
Adam Lancaster · November 2021

Computer systems cost money. We don't often think about this because the value they can provide is large, but none of their work is for free.

For Duffel, that cost comes from processing the large amounts of data involved with sourcing flights and then booking them. To keep those costs manageable and to keep the whole system as efficient as possible, Duffel employs some clever tactics.

Some of our tactics are influenced by the tactics that the airlines use to keep their own systems efficient and cost-effective. Today we're going to talk about one in particular - something called the look-to-book ratio.

What is Look-To-Book?

If you are looking to make a booking, it is required that you first find a flight that is suitable for your customer.

Any given journey has so many factors that can affect price and suitability that it can be frankly baffling. In fact, airline pricing is so complicated it's almost a meme.

Because of this, most travellers will want to perform more than one search  - tweaking parameters like the exact departure date, airline or even the destination airport (eg. Gatwick vs Heathrow) to get a picture of what their options are.

All those variations mean a search is quite resource-intensive for airlines to serve and they often result in megabytes of XML being returned. Figuring out all of the available possibilities for one search requires a lot of computing power - and we fully expect a traveller to perform many searches.

If this was allowed unchecked, it would be an easy way for malicious actors to cost the airlines money just by searching continuously without ever actually making a booking. Even for non-malicious users, there is a theoretical limit on the number of searches an airline can serve before a booking with that airline ends up actually costing them money overall.

To hedge against these risks, most airlines implement a "look-to-book ratio" - a budget of an acceptable number of searches you can make before the airline expects a booking to be made. We can think of it as a sales target - the aim is to make a booking for every X searches. The actual ratios can vary by airline or by the specific contract one might have in place, but the idea is the same.

What is a look-to-book ratio?
A look-to-book ratio is a budget of an acceptable number of searches you can make before an airline expects a booking to be made. Example: 1500:1 means you are expected to make one booking for every 1500 searches.

As a travel seller you want to surface only relevant and interesting offers to travellers, so the goals of the look-to-book ratio are actually in line with what you want too. It means that effort spent understanding your customer's needs before they search can really pay off for you and the airline. But doing this isn't simple, so having the look-to-book constraint - while a good impetus to be efficient - does add some complexity.

What do this mean for you as a travel seller?

You need to be cognisant of what the ratios are for each airline, and should they approach the limit, might in the worst case have to implement mitigation strategies. For example, airlines are shrewd. If you ask American Airlines for a flight from London to Frankfurt, there might be a theoretical option via New York - but that will take 14 hours instead of 2 hours on a direct flight and be more expensive. It is highly unlikely that this would be suitable for a traveller, but that search still counts as a "look".

How Duffel helps

Duffel makes use of what we call our Routing Model. This is a simple model that incorporates information about where airlines fly and attempts to be sensible about who we ask for offers in light of that. For example, if you have a customer interested in flying from Bogota to Santiago de Chile we won’t ask Qantas for flights because we know from their flight schedules that Qantas won't provide relevant results for that route. This saves you a "look" with no extra work! It means travellers can perform more actually relevant "looks" without hurting your look-to-book ratio. This improves customer experience as they wont have to wade through irrelevant offers, all with no extra work on your part!

This model has the potential to get more sophisticated over time - especially as we learn more about macro trends and consumer behaviours - but right now it can save you from having to think about a whole class of problems.

The Routing Model can improve your look-to-book by not "looking" for inappropriate offers in the first place. It can increase customer satisfaction by removing irrelevant noise from their searches. It also means less overall work being done helping to keep the whole system efficient and cost effective, all in all a win-win.

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