Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.

Correlation means two variables tend to vary together; causation means a change in one variable produces a change in another. A correlation can be a clue worth investigating, but it does not, on its own, show that one thing caused the other.

Correlation vs. causation: what’s the difference?

Correlation describes an association between variables. The commonly used correlation coefficient summarizes the direction and strength of a linear association: a positive value indicates that the variables tend to move in the same direction, while a negative value indicates that they tend to move in opposite directions. Causation is a stronger claim: changing one variable would produce a change in the other, under specified conditions.

Correlation is useful for describing patterns and may help predict one value from another. But the same observed pattern can have multiple explanations, so it is not a causal verdict. A correlation coefficient also does not capture every possible relationship: variables can be related in a nonlinear way even when their linear correlation is small or zero. [UC Berkeley: Correlation and Association]

Does correlation imply causation?

No. The phrase “correlation does not imply causation” is a warning against treating an association as proof, not a claim that correlation and causation can never occur together. A cause can create an association; the association alone does not tell you whether that happened.

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.
#1 Best Overall
Elebase USB to USB C Adapter for iPhone 18 Pro Max,USBC Car Charger Adapter
  • Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
  • Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
  • Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
  • Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
  • 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.

An observed relationship could also arise from chance, a third factor, biased selection of people or cases, inaccurate measurement, or other errors in study design or analysis. Statistical significance can help assess the role of chance, but it does not rule out those alternatives or establish cause and effect. [CDC: Analyzing and Interpreting Data]

A third factor can explain the pattern

Suppose a study finds higher mortality among factory workers than office workers. It would be premature to conclude that factory work caused the difference. If factory workers are substantially older, and age is related to both job category and mortality, age could account for some of the association. That third factor is a potential confounder: it is related to both the exposure being studied and the outcome, and can distort the apparent relationship between them. [CDC: Analyzing and Interpreting Data]

Rank #2
Anker USB-C Hub, 5-in-1 USB Hub for Laptops, 4K HDMI Multiport Adapter
  • 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
  • 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
  • Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
  • 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
  • What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.

A shared trend can create an association

Two variables can move together over time without one causing the other. UC Berkeley uses the example of average adult height in the United States increasing while plant species were decreasing. The variables showed a negative correlation, but a direct causal connection is not established by that pattern; the shared time period may help produce the association. [UC Berkeley: Correlation and Association]

A striking example is not a causal explanation

Allan J. Rossman’s statistics-teaching article, “Televisions, Physicians, and Life Expectancy,” compares country-level life expectancy with the number of people per television and per physician. The point is to show how a strong association can be useful to notice without showing that television availability causes longer life expectancy. A variable can help predict another while not being its cause. [Journal of Statistics Education: Televisions, Physicians, and Life Expectancy]

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.
Rank #3
Sale
Anker USB C Hub, 7in1 Multi-Port USB Adapter, 4K@60Hz USBC to HDMI Splitter
  • Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
  • Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
  • Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
  • Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
  • What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.

What a correlation coefficient and scatter plot can—and can’t—tell you

A correlation coefficient compresses a pattern into a summary of linear direction and strength. That summary can be misleading if the relationship is nonlinear or if one unusual observation has a large influence on the result. It also does not establish which variable, if either, affects the other.

A scatter plot can help you inspect the data: look for direction, shape, clusters, and outliers. It can reveal patterns that a single coefficient conceals, but it cannot by itself prove causation. Calling one axis the “independent variable” and the other the “dependent variable” does not establish that the first is causally independent or causes the second. [CDC COVE: Scatter Plot]

Rank #4
Sale
UGREEN USB to USB C Adapter Combo 4-Pack, 10Gbps USB C Converter Space Gray
  • Dual Converters, Infinite Potential:Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
  • Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
  • Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
  • Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
  • Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Support on Ko-Fi

How do you know if one thing causes another?

There is no single checklist item or graph that proves causation. A sound causal argument examines how the evidence was produced, tests plausible alternatives, and considers whether different lines of evidence point in the same direction. Useful questions include:

  • Did the proposed cause come first? The exposure must precede the outcome for it to be a cause.
  • Were the groups comparable? Consider whether they differed in age or other factors that may affect the outcome.
  • Could bias or measurement problems explain the result? Check how people entered the study, how variables were measured, and whether data collection or analysis could distort the comparison.
  • Could the pattern be due to chance? Statistical testing addresses chance, but a statistically significant result can still be biased or confounded.
  • Does the result fit with other evidence? Consistency, a plausible mechanism, and converging evidence can strengthen a case, while alternative explanations still need attention.

These considerations guide judgment; they do not mechanically convert an association into proof. The CDC lists temporal association, consistency, and biologic plausibility among factors to consider. Berkeley’s guidance likewise emphasizes testing alternatives and looking for multiple converging lines of evidence. [CDC: Analyzing and Interpreting Data] [UC Berkeley: Correlation and Association]

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.
Best Value
Anker USB C Hub, 5-in-1 USBC to HDMI Splitter with 4K Display
  • 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
  • Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
  • Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
  • HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
  • What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.

Why randomized experiments offer stronger causal evidence

In a randomized experiment, researchers use chance to assign participants to a treatment or comparison group. Random assignment makes systematic baseline differences less likely on average, helping the groups provide a fairer comparison of outcomes. It does not guarantee that every difference disappears, but it offers stronger protection against confounding than simply observing who received an exposure. [UC Berkeley: Experiments]

Observational studies do not assign exposure this way. People or circumstances determine who is exposed, so the exposed and unexposed groups may differ in ways that also affect the outcome. Careful design and statistical adjustment can help, but adjustment cannot automatically remove confounding—particularly when important factors were not measured. [CDC: Biases to Consider in Vaccine Effectiveness Studies] [UC Berkeley: Experiments]

Randomized trials are not always practical or ethical. Observational evidence can still inform causal questions, but its interpretation depends on the study’s assumptions, potential confounders and biases, and how well it rules out alternative explanations. [From Association to Causation: Some Remarks on the History of Statistics]

Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.

Special offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy.