The use of portable handheld computer technology in the field of health care and clinical research is on the rise, with a corresponding increase in publications. A search of Medline, using the MeSH term "computers, handheld" and text words "handheld computer(s)" combined as "or", revealed a steady increase in the yearly number of publications from none in 1995 to 209 publications in 2003.

The use of handheld computers has been described in a variety of subjects and clinical settings, including: analgesic headache treatments[1]; pain research[2]; bipolar disorder research[3]; asthma research[4, 5]; tobacco use research[6]; orthopedic research[7]; urinary incontinence research[8, 9]; smoking cessation research [10, 11]; brain injury research [12, 13]; menstrual symptom research[14]; field data collection research[15, 16]; diabetes research[17]; eating disorder research[18]; respiratory care research[19]; blood donor research[20]; and adolescent anxiety research[21]. Many of these studies have suggested that handheld technology has several advantages over traditional paper and pencil modes of data capture including but not limited to: data accuracy; timeliness of data capture; and adherence to protocols for data collection.

There are a number of published reviews on the use of handheld computers in the health care setting that focus on design aspects of the handheld device, advantages compared with paper methods, and the clinical applications in which they have been used [22–30]. These reviews provide the reader with much insight but they have limitations when comparing the actual performance of handheld computers with paper methods. Most of the literature is descriptive rather than comparative, focusing on the technology, the methods and/or the experience. When comparing the effectiveness of two methods, descriptive studies have limitations as they lack a comparative control group, and they are prone to publication bias and subject selection bias [31].

Despite the proliferation of literature describing the applications of handheld computers, the number of evidence based publications addressing the efficacy of this technology compared with the traditional method remains few. The purpose of this manuscript is to summarize the literature on randomized controlled trials focusing on the use of handheld computers compared to traditional paper and pencil methods, where at least one of the following outcomes was assessed: data accuracy; timeliness; adherence to protocols; and/or patient preference.

Topics addressed by the nine randomized studies were: Symptoms in patients with overactive bladder[33], appreciation of pain by volunteers[34], collection of chart data by medical students[35], symptoms of patients in an orthopedic clinic[36], rating of appetite by volunteers[37], respiratory data in patients with lung diseases[38], quality of life in patients with gastrointestinal disease[39], food intake by patients with diabetes[40] and factor concentrate use by patients with hemophilia[32]. Three of the studies used a parallel RCT design[32, 36, 39]; whereas, the remaining studies used a randomized crossover design[33–35, 37, 38, 40]. The duration of the follow-up in the studies varied in length but in all cases would be considered short term i.e. same-day experiments[34, 36], follow up lasting two to three days [35, 37, 39]; follow up over a one week period [33]; and two other studies where follow-up lasted one month per arm [38, 40]. One study was carried out over six months[32]. In five of the studies the data collection occurred at the patient's residence[32, 33, 37, 38, 40], while the other four studies were conducted at institutions (i.e.: clinic, physician's office, hospital) [34–36, 39].

The electronic forms of data entry were variable, utilizing push button technology[33, 36], or touch sensitive screens using a stylus pen [34, 37–39]. In one study data were entered via bar codes and an optical reading system[40], while the mode of entry for one study was not clearly specified [35]. In the remaining study [32] data was entered into a handheld computer by a combination of an integrated bar code reader and stylus pen.

Handheld computers and paper and pencil technologies were compared using a variety of applications. In three of the studies subjects were asked to rate some kind of subjective symptom or experience using visual analogue scales (VAS) [33, 34, 37]; whereas in a study of patients with asthma daily symptoms were recorded using custom software[38]. In two of the studies, questionnaires regarding quality of life [39]and quality of care [36] were administered in paper and electronic forms. Three studies examined the abilities of both devices to record objective data such as burn variables[35], daily food intake [40]and intravenous infusions of hemophilic clotting factor concentrates[32].

In three of the studies healthy volunteers/medical students participated to evaluate the two methods of data collection: electronic using a handheld or paper based manual collection [34, 35, 37]. The remaining six studies involved a variety of patient populations including patients with: bladder disorders[33], orthopedic problems[36], chronic obstructive airway disease[38], gastrointestinal problems,[39] diabetes [40] and hemophilia [32]. Summaries of the different studies are given in Table 1.

All, but one of the studies in this review have explored more than one outcome measure[40]. Three studies evaluated the acceptability of handheld computers to patients [32, 33, 36]. In one of these studies acceptability was determined by comparing percentages of positive features reported for each device [36]; the second study measured acceptability using an ease-of-use scale and a face-to-face interview questionnaire to elicit subject's opinions [33]; in the third study [32], acceptability was not assessed but ten (50%) of the patients who had used both paper diary and handheld computer methods subsequently took part in a subsequent qualitative study [41]. Three studies looked at the comparability of handheld computers to paper and pencil devices: two of the studies compared missing and problematic data points [38, 39]; and one study compared results obtained using both paper and electronic visual analogue scales [37]. Two studies explored the equivalence of data obtained by electronic and paper and pencil methods, one used VAS [34], and the other explored differences between group scale scores using the Wilcoxon test [36]. Two studies assessed the validity of electronic modes of data capture: one study attempting to validate an electronic VAS [34]; the other study measuring agreement between conventional and electronic devices in order to validate an innovative device used for data capture pertaining to food intake [40]. The speed and accuracy of both methods were measured in one study [35], as was effectiveness [33] in another. The final study [32] compared adherence to a set schedule for submission of data, accuracy of data, and lag time between data entry in the home and receipt of data at the clinic. Reminder phone calls were made according to a strict protocol.

Despite the numerous investigations describing the potential advantages that hand-held computers offer in research and health care settings compared to traditional paper data collection methods [2, 4, 6, 8, 9, 15, 16, 42, 43] only a handful of these studies adhered to the ideal, experimental method for the evaluation of effectiveness – the RCT (Randomized Controlled Trial)[44]. However, we were able to identify nine studies that comparatively evaluated handheld computers and pencil and paper methods using an RCT crossover or parallel design. The results of this review suggest that handheld computers have the potential not only to overcome some of the limitations of conventional paper and pencil devices but to supersede them, particularly with respect to improving timeliness of data handling. In addition, the preference by research subjects for handheld computers could result in improved adherence to data collection protocols for long-term studies, as evidenced by the markedly improved adherence and patient preference for the handheld computer group in the study having the longest observation period [32].

The importance of data quality from investigator's and sponsors' perspectives has been highlighted elsewhere as the most important issue in considering new data capture technologies [45]. On the other hand an increased accuracy of data entry cannot be assumed for either method. In this review only two of the six studies found handheld computers to be more accurate, in three studies accuracy was similar and in one study the paper method was more accurate. Data entry with handheld computers can in some cases be made relatively foolproof by carefully structuring the questions to allow only determinate types of responses and by the use of prompts to ensure that questions are followed in sequence and cannot be skipped. However, handheld computers will not result in greater accuracy of data where the performance of the paper method is already at a high level or where the source of error is in data collection rather than in data entry or transmission.

Recently, the utility and validity of paper and pencil diaries has been called into question by the findings of Stone et al's [46] suggesting high levels of faked compliance in paper diaries. The same study also demonstrates the capacity of handheld computers to improve and provide objective measures of adherence to protocols by time and date stamping data entries [47]. The authors of one study in this review made similar speculations about retrospective data entry after finding high rates of missing data using handheld computers (designed not to permit retrospective entry) but low rates of missing data in paper diaries [38]. Despite Stone et al's invention and validation of a paper diary equipped with a photo sensor and capable of detecting opening and closing of the diary [47] only one of the studies in this review evaluated direct comparisons of adherence between methods[32]. This latter study evaluated adherence to a set schedule for data transmission rather than evaluating adherence to timely data entry. Future research should be directed towards the endeavor of making direct comparisons of adherence between methods as part of the larger project of validating handhelds for data capture among patient populations.

Differences between the handheld and paper and pencil instruments in data entry, in data handling and transfer times, were seldom evaluated in these studies, yet, theoretically handheld computers offer enormous temporal and financial benefits that deserve further exploration in clinical research. Typically in research vast quantities of data must be collected, organized, and transcribed by key entry into a file using computer software. Often this is done twice (double-data entry) to ensure accuracy and reduce the potential for human error. Using a handheld computer for data collection can eliminate these processes, which are costly and time consuming, resulting in a superior method to conventional paper and pencil devices.

As care and treatment strategies become increasingly patient centered, patient preferences are taken into greater consideration. Preference is defined as the level of desirability that a person associates with a particular health state, treatment process or level of participation [48]. Accordingly, 4 of the 9 studies summarized in this review evaluated patient preferences for either electronic or paper and pencil data capture at the end of the studies. In three out of four of these studies a larger percentage of patients preferred handheld computers to paper and pencil for data capture (Table 4). These findings are important because research has shown that patient satisfaction can influence the efficacy of interventions and levels of compliance [48]; therefore it seems in the interests of the investigator to consider and incorporate patient preferences when choosing a data collection tool. A recent study from our centre has also shown that method of record keeping is an important factor contributing to adherence of reporting [41].

The analysis of these studies provides evidence that handheld computer devices are an effective technology for data collection in the health care setting and in health related research. When compared to paper and pencil methods of data recording the handheld computers appear to be faster and preferred by most patients. The accuracy of the data collected may be greater with handheld computers in some circumstances but not all and the definitions of accuracy varied between studies. Future studies in this area would benefit from a more standardized definition of accuracy to allow for inter-study comparisons of results. As well, additional information to assess adherence to data collection requirements would also be useful as part of the overall assessment of the usefulness of handheld computer technology for data collection in the health care setting.

Recently, a number of authors have stressed the limitations of randomized trials in assessing the role of computer systems, indicating that questions such as how and why computer systems are used and explanations of various phenomena are best answered by studies based on qualitative, technical, psychological and other methods [49–51]. None of these authors are however suggesting that randomized trials be abandoned, and in fact are suggesting an integrated approach involving both quantitative and qualitative methods. Our opinion is that the randomized trial is best suited for comparing the ultimate performance of two or more methods in their actual clinical settings. Questions of generalizability to situations outside the actual test conditions will arise, but this is well understood. We suggest that the emphasis, though not the only role, of other methods is in the explanation of observed phenomena and in the actual development of systems. In deciding on a method of data collection, researchers could reasonably consider that handheld computers will likely be acceptable to patients and have the potential to provide more rapid data handling. On the other hand, improved compliance and accuracy of data recording should not be assumed and may depend on the particular conditions of the study, the origin of these aspects may lie outside the nature of the recording device, such as in training, understanding and motivation.

These studies illustrate many of the technical qualities of handheld computers described in previous reviews and are highlighted by their direct comparison with those of the paper standard when these methods are used side by side. Handheld computers can be programmed to provide determinate responses, date stamped to document times of data entry, restrict times of data entry, prevent retroactive data entry, limit 'look back' to previous data, prevent omissions of data entry, and can save considerable time and labor incurred in data handling. Handheld computers are well accepted, and are more likely than paper methods to be the choice of the user. The ultimate results with handheld computers have in most trials been similar to those of the paper method, particularly when the performance of the paper method is already high, and therefore improved accuracy cannot be assumed. The potential advantages of handheld computers lie in their technical advantages which should be carefully considered when designing the software programs to match the task.