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Evaluating Mobile Health Tools Is Comparing Apples to Oranges

There’s still no codified way to measure digital tools’ effectiveness in different cultural and social cohorts

4 min read
Illustration of hands holding a phone. There is a medical symbol in the background with colored lines coming out of it in a disarrayed pattern.

Like a doctor on one’s wrist, mobile health (mHealth) tools offer the promise of providing personal physiological data on demand.

How many steps did you take today? Press the button. What’s your current heart rate or amount of oxygen in your blood? Push the button. Glucose level? Scan the sensor on your arm.

Unlike a human physician or nurse, though, the digital tools and the mobile apps they often pair with have no way of identifying how each user might respond to them. What might be motivating for one person, such as a personalized encouraging message, may seem intrusive to another. A study published in Management Information Systems Quarterly in February 2022 examined a digital diabetes management tool through the experiences of 1,070 patients in Asia. The study’s authors found a generic SMS messaging scheme was 18 percent more effective in lowering a patient’s glucose level than a personalized patient-specific message string.

Moreover, the authors found, “personalization is not as effective as non-personalization if we try to improve diabetes patients’ engagement with the app usage or general life style (i.e., sleeping behavior or movement habits). This is likely because patients might perceive frequent personalized SMS messages as intrusive and annoying.”

The authors—a group of researchers at Carnegie Mellon University, in Pittsburgh, Harbin Institute of Technology, in China, and New York University—add that “these findings are surprising and suggest personalized messaging may not always work in the context of mHealth, and the design of the mHealth platform is critical in achieving better patient health outcomes.”

And, according to those who study the field, there isn’t yet a common approach to assessing the effectiveness of developers’ and researchers’ cultural adaptation of these tools, including aspects of personalization, for different user bases.

“The implementation science around how to translate digital health tools that perform well in silico into real-world utility, in the form of desired behavior change and better patient outcomes, is still a very nascent field. There is still a lot of work to be done,” says Jayson Marwaha, a postdoctoral research fellow at Harvard University.

Some researchers have tackled the issue of adapting mHealth tools to different cultures. For instance, in 2020 a team at the Zurich University of Applied Sciences published a comparison survey of Swiss and Chinese consumers and found markedly different reasons why a person might use one depending on the culture of each nation.

A Swiss consumer might start using an mHealth tool based on a physician’s endorsement and evidence that the device was accurate, they found. A Chinese consumer, however, would be more likely to consider the opinions of members of their social circle and employers, as well as devices that could augment a stretched-thin health system with credible advice.

The Zurich University team hasn’t pursued the cultural components of Internet or mHealth tool acceptance further. But another group, at the University of Freiburg and Ulm University, in Germany, has in several meta-analyses. Those analyses have found that evaluating the efficacy of these interventions is still very much an apples-to-oranges situation, which may be inhibiting faster and wider adoption of them.

For example, one of the Ulm researchers, Sümeyye Balci, said the tone of SMS messaging is just one aspect of trying to keep participants motivated to keep going with a trial in which they are enrolled.

“The bigger issue in cultural adaptation studies is that we still don’t know to what extent we should adapt an intervention’s content or delivery method, and for which population,” Balci said. “So it’s not entirely clear what works best for which group and what behavior. That’s what we’re trying to understand in our group.”

Balci and her colleagues have laid out 17 discrete components of cultural adaptation that should be considered in deploying a digital tool (Internet-based or mobile) in disparate cultural groups. They outlined these components in the context of mental-health tools, but Balci says they could be used for any tool for any condition; some elements could be given less weight or discarded entirely, depending on the tool’s purpose. For instance, intense personalization may be deemed intrusive by one group for a diabetes tool—such as the Carnegie Mellon/Harbin/New York University group found—but expected and welcomed for a behavioral therapy app.

Marwaha recently coauthored an editorial in NPJ Digital Medicine that called for digital health-tool developers to use those 17 components as a guide when deploying tools across disparate populations. “I think it is a very helpful initial attempt at reducing heterogeneity in how people do these kinds of adaptation efforts,” he said. “Identifying a comprehensive list of all the things you should consider is an incredibly important start.”

The Freiburg/Ulm group’s latest study is a meta-analysis of 13 studies that looks at mHealth cultural-adaptation efforts across the subjects of healthy eating, physical activity, alcohol consumption, sexual-health behavior, and smoking cessation. The results led the group to conclude that those efforts currently haven’t shown they are worth the effort (only culturally adapted physical activity platforms were superior to control group results). But neither Balci nor Marwaha say that means cultural adaptations aren’t important. Balci says the paper isn’t meant as an argument to halt them entirely, but rather to find common ground in how best to measure their effectiveness: “We should work on specifying to what extent we should do it, or for which population we should do it.”

Likewise, Marwaha says that concluding that such personalization and adaptation isn’t important is the wrong idea. Instead, he said, “it will just take further study to figure out how to do it right and how to do it in a standardized, consistent fashion. The way researchers are doing it now—at least as seen in the data—doesn’t seem to be improving the clinical impact of these tools, and the clinical impact is what really matters.”

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

This article appears in the February 2023 print issue.