 Systematic reviews and systematic maps are specific methods for reviewing research literature that aim to maximize transparency, objectivity, and comprehensiveness. And they do that by having a suite of methods along the process of conducting a review that are each stage aimed to maximize those things. And it starts out, for example, by establishing the methods that you plan to use in a protocol and having that peer reviewed and having the methods behind it produced through a consensus of your review group. And the methods that you then use to conduct the review will include things like searching across multiple databases, using a tried and tested search string, screening articles for relevance against an a priori pre-established set of inclusion criteria, and extracting data in a specific way and synthesizing it according to the plans that you set out at the beginning. And the reason that we have systematic reviews and systematic maps is that the traditional way that we might synthesize literature from an evidence base could be susceptible to a number of different biases. For example, if someone was to conduct a review or a meta-analysis, let's say, but based that on studies that they're already familiar with, maybe they go to a shelf and take off articles that they've been collecting. The problem there would be that subconscious bias or potentially deliberate bias could creep in. And the results that you get might not be representative of the real body of evidence. So I've been working with systematic reviews for a number of years across a range of different topics. Sometimes these have been dedicated systematic review projects, but often when we start a project, we want to know the state of knowledge on a particular topic. So many projects have a literature review as the first part of their work package or their work as a whole. And that's the case with a recent project I've been working on called Bonus Return, which has had a systematic review as one work package within a longer, more elaborate suite of different studies. And so in this project, we've conducted a systematic map or two very closely related systematic maps looking at what ecotechnologies have been used to reuse carbon and nutrients, and it's particularly relevant to the Baltic Sea. So within the Bonus Return project, we actually started off before conducting the systematic maps, conducting a very quick thematic synthesis it's called, where we weren't quite sure what people meant by the term ecotechnology. So we conducted a systematic review of research literature where people had talked about the word ecotechnology in various different forms and tried to build a conceptual model of what people meant by the word ecotechnology so that we could be sure what was relevant and what wasn't relevant to the project that we then undertook with two later systematic maps. And that thematic synthesis really helped us to define what an ecotechnology is. So when we think about how long it takes to conduct a systematic review or a systematic map, it's a little bit like how long is a piece of string. They really take a huge range of different times. Some can be very quick. I've been involved with one that took about six weeks. Some can be quite time consuming. So one of my colleagues recently conducted took about four or five years. But it really depends, firstly, how big the evidence base you're dealing with is. And secondly, how detailed you are, the kind of information you're extracting and the kind of synthesis that you want to conduct. There are always processes where you have to pause and think and that reflection can take quite a long time. But we've recently conducted an analysis of the amount of time that's needed for a systematic review or a systematic map. And that's based on around 80 reviews and maps that are published by the Collaboration for Environmental Evidence, which is an organization that coordinates review and map publishing. And we found that, on average, it takes, I think, around 164 days of person hours or person time for a systematic review and about 206, I think, days for a systematic map. But the variability around those estimates is quite large. So we've used those data to produce a tool called predictor.org. And that tool allows people to tweak the defaults a little bit to tailor the estimation of how long it takes to conduct a review or a map to their own project. So they might know, for example, how many search results they're likely to get. Or they might know certain activities that they definitely want to do and some that they don't. And they can use that tool to get an estimation of how long it's likely to take. So if I was asked to give some tips or advice for someone who might want to do a systematic review or a systematic map, I think the first thing I'd say would be to connect with one of the many communities that is a kind of community of practice and network of people who are interested in systematic reviews and maps and their methods. And there are various organizations that do this. There's the Collaboration for Environmental Evidence, CE, who work in environmental subjects. There's the Cochrane Collaboration, what's now called Cochrane, who work in the field of health care. And Campbell, who work in social welfare, crime injustice, and international development. And there's some overlap in the scope of these communities, but each one is a voluntary group of people who are very interested in the methodology. And they have a lot of advice and support in terms of guidance documents or helpful advice for people who are starting out. And there are a lot of methodology articles as well that can provide advice for various different steps along the way. Maybe the easiest thing to do is connect with someone who's conducted a systematic review. But everyone's very friendly, so it's very easy to reach out and ask a question.