How to Create a Trend Report in Looker
Tracking your business performance over time is fundamental to understanding what’s working and what isn’t. A trend report helps you cut through the noise of daily numbers to see the bigger picture, showing you the direction your key metrics are heading. This guide will walk you through how to create a clear, actionable trend report in Looker (now part of Google Cloud).
What Exactly Is a Trend Report?
At its core, a trend report is a visualization that charts one or more key performance indicators (KPIs) over a specific period. Instead of just looking at last month's sales number in isolation, a trend report plots that number alongside the sales from the previous 12 months. This context is everything.
With a well-built trend report, you can:
Spot Seasonality: Do sales consistently dip in the summer and spike in Q4? Seeing this pattern helps you plan inventory, marketing spend, and staffing.
Measure Growth: Are your website sessions slowly climbing month-over-month? A trend report makes it easy to visualize your long-term growth trajectory, not just weekly fluctuations.
Identify Problems Early: A sudden, sharp decline in user engagement that breaks from the normal trend is a red flag. A report helps you catch these issues before they turn into major problems.
Assess Campaign Impact: You can overlay key events, like the launch of a new marketing campaign, to see if they created a tangible lift in performance.
Whether you're tracking weekly website visitors, monthly recurring revenue, or daily customer support tickets, seeing that data trended over time turns a list of numbers into a powerful strategic story.
Key Looker Concepts for Trend Analysis
Before jumping into the build, it helps to be comfortable with a few core components of Looker. Understanding these terms will make the process much more intuitive.
Dimensions vs. Measures
This is the most critical concept to grasp for reporting in Looker (and most BI tools). It's simpler than it sounds:
Dimensions: These are the things you want to group or categorize your data by. They are descriptive attributes. For a trend report, the most important dimension will always be a time-based field, like a Date, Week, or Month. Other examples include Campaign Name, Country, or Product Category. Think of them as the "who," "what," or "where."
Measures: These are the numbers you want to analyze - the quantitative values. Measures are the result of an aggregation or calculation, like a Count of Users, Sum of Revenue, or Average Order Value. Think of them as the "how many" or "how much."
To create a trend report, you’ll plot a measure (like Total Sales) against a time-based dimension (like Month).
Explores
An "Explore" is simply your starting point for asking questions of your data. It’s a curated dataset designed for a specific area of analysis, like "Web Analytics" or "Sales Orders." When you want to build a report, your first step will always be to choose the right Explore that contains the dimensions and measures you need.
Step-by-Step: Building a Trend Report in Looker
Let's build a common and useful report: a simple line chart showing weekly user sessions over the last 90 days. This will help us understand our website traffic patterns.
Step 1: Select Your Explore
Once you're logged into Looker, navigate to the Explore section from the main menu. You'll see a list of available data models. For our example, we would choose an Explore related to our web analytics data, which might be named something like "Website Traffic" or "Google Analytics Data."
Step 2: Choose Your Time Dimension
On the left-hand sidebar, you'll see all the available dimensions and measures. Our first goal is to find the time-based dimension. It will likely be nested under a group with a name like "Events" or "Users." Look for a dimension called something like "Event Date," "Created Date," or simply "Date."
Looker makes it easy to group by different timeframes. Click on the dimension, and you should see options to group it by Day, Week, Month, Quarter, or Year. For our report, select Week.
Now, this specific time dimension is added to your query.
Step 3: Select Your Measure
Next, find the metric you want to track over time. Staying in the left-hand sidebar, look for the "Measures" section (they are usually a different color, often orange or blue). We want to find a measure that counts user sessions. It might be called "Session Count," "Number of Sessions," or "Total Users." Click on it to add it to your query.
You should now have one timeframe dimension (Week) and one measure (Session Count) selected.
Step 4: Filter Your Date Range
By default, Looker might pull an enormous amount of data. To keep our report focused, we need to apply a filter. Find the Filters section at the top of the page. Add your time dimension ("Event Date") as a filter. A set of filter options will appear. Choose a logical range, like "is in the last 90 days."
After setting the filter, you can press the Run button at the top right. This executes the query, and you'll see a data table appear with two columns: your Weeks and a count of Sessions for each week.
Step 5: Create the Visualization
A table of numbers is hard to interpret. Let's turn it into a chart.
Navigate to the Visualization tab next to the "Data" tab.
Looker often defaults to a reasonable chart type, but if not, click on the chart options. For a trend report, a Line chart is almost always the best choice. Select it.
Use the Edit button (usually a cog icon) to open the visualization settings. Here, you can clean up your chart to make it more professional:
Give your axes titles (e.g., "Week" for the X-axis and "Total Sessions" for the Y-axis).
Add a helpful chart title like "Weekly Website Sessions (Last 90 Days)."
Adjust colors to match your brand if needed.
That's it! You now have a clear, easy-to-read trend report showing your website traffic patterns over the past three months.
Going Further: Advanced Trend Analysis Techniques
Once you’ve mastered the basics, you can add more layers of detail to your trend reports to uncover deeper insights.
Using Pivots to Compare Segments
What if you want to see if your mobile traffic is growing faster than your desktop traffic? You can visualize both trends on the same chart using a Pivot.
Go back to your field list on the left. Find a dimension that segments your audience, like "Device Category."
Instead of just clicking it, click the pivot icon next to it.
Click Run again.
Your data table will now be reconfigured. In the visualization tab, Looker will automatically create separate lines for each device category (e.g., one line for "mobile," one for "desktop," and one for "tablet"). This is an incredibly powerful way to compare the performance of different segments over the same time period.
Adding a Trend Line
Sometimes you want a general sense of the data's direction, smoothing out the weekly or monthly bumps. In the visualization settings, look for an option to add a Trend Line. You can often choose from several types, but "Linear" is a great place to start. This will overlay a straight line on your chart, making it immediately obvious whether the overall trend is positive, negative, or flat.
Saving and Sharing Your Report
Once your report is perfect, you don't want to have to rebuild it every time.
Save it as a Look: Click the gear icon in the top right and choose "Save as a Look." Give it a descriptive name so you and your team can easily find it later.
Add it to a Dashboard: You can also add your new report to a dashboard alongside other key visualizations. This creates a central hub for all your most important KPIs, where everything updates automatically.
Final Thoughts
Creating a trend report in Looker is a foundational skill for anyone serious about making data-driven decisions. By simply plotting your key metrics against a time dimension, you unlock valuable insights about growth, seasonality, and the overall health of your operations that you'd otherwise miss.
While Looker is a powerful tool, getting started sometimes involves a learning curve around concepts like Explores, dimensions, and measures. At Graphed, we created a platform that removes this friction by letting you build these same reports using natural language. You can simply connect your data sources like Google Analytics or Shopify and ask, "Show me a line chart of my website sessions by week for the last 90 days," and our AI will create the interactive chart for you, no need to navigate menus or select fields manually.