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Project Overview

This research project was done as part of the coursework for the MS. HCDE program and was sponsored by Samsung Research America. Samsung sought to get an in-depth understanding of the motivation and practices employed by people using tools for weight management. Participants were recruited for a week-long diary study, which gathered observations on  how they used Fitbit in their native environment to manage their weight, tools that resonate with users, and obstacles they face in reaching their objective. The results and findings from the study were reported to the executive team from Samsung Mobile Innovation Lab in California.


To explore how and why people use tools for weight management. Identify which tools resonate with users, and uncover obstacles they face as they use them.

The Work

A week-long diary study was conducted to understand how participants use "Fitbit" (wearable device) in their native environment to manage their weight.


Work with a limited budget to recruit participants willing to contribute time for a week-long study.  Select participants motivated by the goals of the project rather than gratuity.


Executive-level presentation to key management stakeholders from the SAMSUNG Mobile Innovation Lab .

Project Scope

Our objective  is to research current weight management tools and services in order to specifically understand:


  •    Why do people start using tools to manage their weight?

  •    How do they use tools to manage their weight?

  •    What motivates people to continue managing their weight?

  •    What obstacles do people find in managing their weight?





Research Question

Samsung Research America would like to learn about the various tools that people use for weight management, which ones resonate with users, and why.

Research Question
Project Scope
Research Process






Background Information

Literature Review:  Our team surveyed literature exploring weight management, food journaling, motivations and obstacles for weight management  and user retention over time. We also explored user retention through previously published research.

  • In the US. alone, 29.1 million people have Diabetes.

  • 600,000 Americans die from Heart Disease each year.

  • Obesity is a major contributor to Diabetes and Heart Disease.

Competitive Analysis: I performed a survey of current weight management tools and services to identify the most popular ones. As a team,  we decided to focus on the use of  the Fitbit, as it is the market leader in wearable devices, as per 2013 consumer reports.


Target User

User Profile: We identified the target population segment for a usability study. Examples of user segments based on their goals  include: Pre- Diabetic, tech savvy, athletes, and repeat weight loss seekers, weight management seekers.

Identify Primary Persona: From the short list of user profiles, the primary focus for this project  was selected as “Weight Management Seekers.” These users have a clear goal as their motivation (lose or maintain weight). We expected  that these participants would demonstrate commitment and  adhere to the study protocol. We also expected that these users provide us with a set of reliable, high quality data for further analysis. 

Categorize Persona:  Next, we classified this  user segment into 2 categories: novice users are those who have never used a Fitbit device (nor any other smart wearable devices), and experienced user- who have actively used a Fitbit device for at least three months:

  • From novice users, we gain insights into deep-seated issues that may arise from the way they learn to incorporate the device and app into their weight management activities.

  • From experienced users, we hope to understand conditions for continued use and  whether their  evolving needs are met or not by the device and app.

Recruit Participants: 

We defined a Novice participant as someone who had never used a Fitbit device of any kind, nor any other wearable devices. Experienced participants in this study had used their Fitbit device for at least three months. We used a set of criteria (including demographics, experience, ability to participate, occupation & geography) to screen and qualify participants.

We were able to recruit a total of ten participants -- five Novice participants and five Experienced participants, in accordance to our user profiles. We used convenience and snowball sampling methods to satisfy our time constraint. We used each team member’s personal networks as well as Facebook to recruit potential participants. 


Usability Studies


A week-long Diary Study was conducted to understand how participants use Fitbit in their native environment to manage their weight. In the context of our research, "weight management" was defined  as either seeking to lose weight or seeking to maintain weight at a certain level. 

Selecting a Wearable Device for the Study


The Fitbit was chosen by the design team as the device for the diary study.

The Fitbit was chosen after a competitive analysis to review:

  1. Seven competitive devices with a range of features (Fitbit Flex, Misfit Shine, Basis Peak, Jawbone Up24, Nike+ Fuelband SE, Withings O2, and Garmin Vivofit)

  2. Device features such as calorie tracking, step counting, and price.

Although the Fitbit Flex did not have advanced features that many devices had, it provided users with wider-ranging options to track behavioral health indicators rather than biological indicators, such as a heart rate monitor. Further, since Fitbit Flex falls within the average price range, we felt it fit well within the scope of our study.

Finally, Fitbit is the market leader, and accounted for 68% of the sales of all activity tracking devices (based on survey data from 2013).  By studying a market leader, we intended to test best-in-class functionalities as well as gain insights from a wider sample of users. 

Why Diary Study?

A diary study enables participants to disclose more than they might have through other methods, leading to a more accurate representation of their device use. The main advantage of this method is that it allows us to track longitudinal usage patterns of wearable devices.


Feedback and responses were collected daily so there was less lag in data collection. By conducting a remote study, we hoped to gather information about participants’ behaviors as well as their interactions with the device that might otherwise not have been possible with interviews or surveys.

Finally, a diary study is excellent for finding emergent behaviors embedded in participants’ daily lives that is hard to obtain from observing or from interviews.

Diary Study Design

The design team developed the framework and design for the diary study during focused brain storming sessions. An "Affinity Diagram" was used to capture the output of these discussions, map study components with their relationships, and organize our thinking into actionable steps.

Affinity Diagram

We conducted a seven-day diary study in which daily emails containing 5-8 questions were sent to all participants. We collected responses from every participant at the end of each day to avoid loss of data and ensure its accuracy. We gave participants the entire day to record their responses to capture a full range of data and increase the flexibility of the study. 

The questions were embedded in Google Forms, and each form contained a set of core questions as well as a set of questions specific to either Novice or Experienced participants. While the core questions were common across both groups, the additional questions varied each day according to a theme that assessed differences between Experienced and Novice participants. Each day’s theme focused on different aspects of weight management, and are identified under "Diary Study Themes" below.

Study Content

The study comprised a set of core questions as well as a set of questions adapted to the specific personas of novice and experienced users.

Study Protocol

Before commencement of the Study, participants were briefed on the process and given instructions on how to record their responses a day before. Participants received an email containing the day’s questions in the morning, and returned their responses through email by the end of the day. One email reminder was sent to all participants every day to ensure they send in their responses on time. At the end of one week, we debriefed all participants, answered any additional questions about the study, and provided them with their incentive. 

After the diary study, we followed up with four participants individually for a post-study interview. We selected two Novice and two Experienced participants to gather more in-depth answers to their diary study responses.  

Research Process
Diary Study