Psychological Methods 2006, Vol. 11, No. 1, 106 –111
Copyright 2006 by the American Psychological Association 1082-989X/06/$12.00 DOI: 10.1037/1082-989X.11.1.106
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Paper and Electronic Diaries: Too Early for Conclusions on Compliance Rates and Their Effects—Comment on Green, Rafaeli, Bolger, Shrout, and Reis (2006) Joan E. Broderick and Arthur A. Stone Stony Brook University This commentary discusses 4 issues relevant to interpretation of A. S. Green, E. Rafaeli, N. Bolger, P. E. Shrout, and H. T. Reis’s (2006) article: (a) Self-reported compliance in medical settings has generally been substantially higher than verified compliance, suggesting that this is not a rare phenomenon; (b) none of the studies reported in Green et al. explicitly verified paper diary compliance; (c) the impact of participant motivation on diary compliance is unknown, and it may be difficult for researchers to accurately assess it in their own studies; and (d) without objective verification of diary compliance, analysis of the effects of noncompliance on data quality is difficult to interpret. The authors conclude that compliance in paper diaries and the effects of noncompliance on data quality are still unsettled issues. Keywords: self-report, diary, compliance, adherence, research methods
ipants and that raise questions about its impact on our data. Green and colleagues (2006) have written a thoughtful piece compiling data from three diary studies conducted at different laboratories with varied participant samples, diary sampling schedules, and types of experiences being monitored. They not only addressed compliance across the three studies but also conducted analyses on the comparability of data collected with paper and electronic diaries. In this commentary we challenge several of the assumptions and conclusions advanced in Green et al.’s article, although we agree with their general conclusions that many essential questions about compliance in paper and electronic diaries remain unresolved. There are a number of very detailed issues that we could discuss given the complexity of the three studies, but instead we focus this commentary on four overarching issues suggested by Green et al.’s (2006) conclusion. The major points we make are (a) that the research literature on compliance reports many examples of poor compliance and should prompt a more conservative position than that advanced by Green and colleagues; (b) that the assumptions made about their techniques for assessing actual compliance may be incorrect; (c) that the assertion that their studies had highly motivated participants, which led to high compliance, is not supportable; and (d) that the conclusion that there were no differences in data collected with paper versus plastic was not adequately tested in the reported research.
We appreciate the opportunity to participate in this discussion of compliance with self-report diaries through this commentary on Green, Rafaeli, Bolger, Shrout, and Reis’s (2006) article. In part, their article was written in response to two studies published by our laboratory that found objective evidence of very poor compliance with paper diaries in the face of high levels of self-reported compliance (Broderick, Schwartz, Shiffman, Hufford, & Stone, 2003; Hufford, Stone, Shiffman, Schwartz, & Broderick, 2002; Stone, Shiffman, Schwartz, Broderick, & Hufford, 2002). In recent years, use of paper diaries has dramatically increased in a variety of medical, psychological, and social studies. It is quite distressing for all of us conducting this type of research to encounter data that contradict our subjective impressions of satisfactory compliance by our research partic-
Joan E. Broderick and Arthur A. Stone, Department of Psychiatry and Behavioral Science, Stony Brook University. Arthur A. Stone is associate chair of the Scientific Advisory Board of invivodata (Pittsburgh, PA), a company that provides electronic diary capture services to industry. This work was supported in part by National Cancer Institute Grant CA-85819 to Arthur A. Stone. Correspondence concerning this article should be addressed to Joan E. Broderick, Department of Psychiatry and Behavioral Science, Putnam Hall, Stony Brook University, Stony Brook, NY 11794-8790. E-mail:
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Compliance Research More Broadly Considered There are undoubtedly a good number of paper diary studies that have had the good fortune of receiving highly compliant data from participants. Nevertheless, our research reports of substantial discrepancies between self-reported and verified compliance sounded an alarm that compliance in at least some paper diary protocols may be substantially lower than researchers presumed based on self-reported compliance. What other literature is available to inform us of the extent that noncompliance may be a problem? Although investigations of diary compliance have a relatively short history, there is an extensive literature for other forms of self-monitoring that examined comparisons of self-reported versus verified compliance including medication use and collection of physiological and biological data. To provide a context for the discussion of Green et al.’s (2006) findings, we provide the reader with a brief summary of what is known about levels of compliance with medication and other devices wherein participants are instructed to follow a well-defined protocol and compliance is objectively monitored. Medication-compliance research consistently comes to the resounding conclusion that it is common for people to misrepresent their compliance on self-report relative to objective indices (Osterberg & Blaschke, 2005). The tone of the medication-compliance literature has striking similarities to the current discussion. In 1998, Urquhart and DeKlerk wrote, “Electronic and chemical marker methods provide the first reliable measurements of drug exposure in ambulatory trials. These data contradict the usual claim in published drug trials of ⬎90% of patients having been satisfactorily compliant with the protocol-specified dosing regimen” (p. 251). Patient compliance with medication dosing has been found to be a significant problem, with patients frequently inflating rates of compliance in self-report to providers and in diaries (Boudes, 1998; Mallion, Baguet, Siche, Tremel, & de Gaudemaris, 1998; Urquhart, 1996). The terms parking lot compliance and dumping were coined to describe the common practice of off-loading medication just prior to a research or clinical visit so that the patient appears to have used the prescribed amount of medication since the last visit (Rand et al., 1992). Likewise, diary entries of physiological monitoring have been shown to have varying degrees of correspondence to the data collected by electronic monitors. Studies of the accuracy of glucose monitoring in diabetics has compared the glucose levels recorded by patients in their logbooks versus the electronic reading in the monitor. Mazze et al. (1984) found that 26% of logbook recordings among 19 diabetics across 12–14 days did not correspond with the electronic glucose monitor, and in two thirds of those cases, the self-reported glucose levels were lower. Similar results were found in other studies (Gonder-Frederick, Julian, Cox,
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Clarke, & Carter, 1988; Williams et al., 1988), including evidence of insertion of “phantom values” (Mazze et al., 1984; Ziegler et al., 1989). Other studies involving blood pressure monitoring have observed discrepancies of 10%– 20% (Cheng, Studdiford, Chambers, Diamond, & Paynter, 2002; Ciree, Hanon, Bureau, Mourad, & Girerd, 2001) to 32% (Johnson, Partsch, Rippole, & McVey, 1999) in patient-recorded blood pressure readings compared with the electronic record generated by the blood pressure monitor. In some cases the noncompliance with reporting did not result in significant differences in blood pressure values (Cheng et al., 2002), whereas in others it did (Johnson et al., 1999; Nordmann, Frach, Walker, Martina, & Battegay, 2000). Finally, sampling of saliva to assay for cortisol has become common. Because of the biologically determined circadian cycle that controls cortisol release, precise recording of when the saliva samples are taken is essential for accurate interpretation of the data. Broderick and colleagues conducted two studies (one with healthy college students and the second with both healthy women and fibromyalgia patients; Broderick, Arnold, Kudielka, & Kirschbaum, 2004; Kudielka, Broderick, & Kirschbaum, 2003) and found that in this context, as well, self-report of saliva sampling deviated from electronically recorded sampling times at a level sufficient to significantly alter the interpretation of the data. We would all like patients and research participants to adhere to our instructions and to accurately report their behavior to us. Unfortunately, in the majority of cases using objective monitoring, it is typical for verified compliance to be less than optimal and for participants to inflate their reports of compliance. When a person believes that his or her actual behavior cannot be detected, it may be human nature to modify self-presentation to be consistent with expectations. Although self-monitoring of disease states may introduce special influences on the accuracy of recording,1 we suggest that these observations should give pause to diary researchers. Diary entries for internal experiences or behaviors may be categorically different than entries for physiological monitoring or drug administration. Likewise, different samples (clinical patients or college students) may yield different compliance patterns. Ultimately, this is an empirical question, but we suggest that there may be more about human nature that is shared across these content and sample domains than is different. What seems compelling to 1
We speculate that there are likely several factors that may influence patients’ desire to misrepresent their compliance with a diary protocol. Among these are the fears that noncompliance will endanger one’s relationship with the health care professional, concern that noncompliance in a research protocol could result in termination of access to medication or other treatment, or discomfort with self-monitoring of indicators of pathology such as elevated glucose or blood pressure.
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us is that the findings of our diary compliance studies (self-reports of pain and mood) are consistent with the medical compliance literature using objective verification procedures, and Green et al.’s (2006) conclusions are not. As such, it is disappointing that Green and colleagues did not consider their findings in the context of this broader compliance literature. Had they done so, they might have applied a more critical eye to their methods and data and, perhaps, have tempered their conclusions.
Verifying Diary Compliance Green and colleagues (2006) make a strong argument for good compliance with paper diaries on the basis of the random-signaling protocol that was used in Study 1. Of the entries that were completed, 90% of the self-reported times were within 20 min of the random signal. Green et al. argued that it is “implausible” to think that participants would have made the effort to record the time of diary prompt and would not have completed the diary ratings at the same time. However, what one thinks is reasonable and what actually happens may be different things. In one of the only random-signal studies that extensively debriefed paper diary participants, although the participants appeared to have 81% compliance with signaled entries, actual compliance was much lower (Litt, Cooney, & Morse, 1998). During the debriefing, 70% of the participants revealed that they recorded the correct signal time on their diary cards but did not complete the actual diary questions until some time later. In some cases, it was only a few minutes later, yet sometimes it was hours later, and in one case all entries were made at once at the end of the day. One might argue that Litt et al.’s (1998) finding is not generalizable because participants were alcoholics and were perhaps inherently unreliable. However, in another similar protocol with the same population that was conducted subsequently with electronic diaries, Litt and colleagues observed an average of 91% compliance (range ⫽ 49%–100%), suggesting that the participants were not inevitably unreliable. Thus, as we found in our studies, compliance computed on the selfreported time of diary completion is significantly higher than actual compliance, and participants who have poor compliance with paper diaries are able to be highly compliant with electronic diaries. It is, of course, possible that participants can be compliant with a paper diary protocol, but it is probably naive to uncritically accept that assumption when based solely on self-report, especially in the face of Litt et al.’s (1998) results. Not one of the studies reported by Green et al. (2006) objectively verified paper diary compliance. The only studies to date with objective verification of compliance with paper diaries are those from our laboratory (Broderick et al., 2003; Stone, Shiffman, Schwartz, Broderick, & Hufford, 2003), and these discovered a wide chasm between
the compliance that patients self-reported and what was objectively verified. On the other hand, we must also say that our results are limited to the particular fixed-time, within-day sampling protocol used in those studies, and we make no claim that those results generalize to other sampling protocols. In fact, we suspect that low-burden, endof-day paper diaries, for example, would yield higher compliance levels than would those reported in our previous studies that involved multiple entries per day. It is important to point this out, because some have taken our results and overgeneralized them to all paper diary research. We believe that research examining the parameters that contribute to compliance levels (e.g., awareness that one is being monitored, sampling density, participant characteristics) is sorely needed.
Participant Motivation and Compliance The issue of participant motivation and its effect on compliance with diary protocols is a central theme in Green et al.’s (2006) article. They asserted that high levels of motivation generate satisfactory compliance: “In broad terms, the results of these studies suggest that compliance is much more an issue of study design and participant motivation than it is an issue of whether a diary is administered in paper-and-pencil form or electronically” (Green et al., 2006, p. 102). Certainly, common sense would suggest that any well-motivated individual will perform better than a poorly motivated one. However in the current context, we do not think there is any evidence that motivation will necessarily express itself as behavioral compliance. Rather, once a participant is in the field and the demands of the protocol are apparent, motivation may primarily be expressed in self-presentation as a good research participant or a good clinical patient, even when one’s behavior falls short. Thus in diary studies, although participant motivation might be at a high level in particular studies, at this point we do not know whether it will manifest itself as increased actual compliance with protocol or, instead, only as high levels of self-reported compliance motivated by the desire to be a good participant. There also exists the possibility that high levels of participant motivation are actually associated with higher levels of falsification of time of diary entries in order to generate the most complete data set for the researcher. Furthermore, high levels of motivation could negatively impact quality of data. Some participants who are highly motivated might generate many entries, thus being compliant, yet the quality of their responses might be poor: a quantity versus quality problem. This later issue applies to any form of diary data collection, including electronic. Thus, we believe that levels of participant motivation cannot be assumed to have a simple or, at this point, predictable association with diary entry compliance.
COMMENTS
A second point concerns Green et al.’s (2006) contentionthat the investigators of their three studies engaged with participants in an especially effective and collaborative way, thus eliciting high levels of motivation and cooperation and achieving high protocol compliance. We do not question that they established high motivation through a collaborative partnership with study participants. We believe that many researchers would self-assess their relationship with study participants as an exciting and respectful partnership. What we think is unfounded is the untested conclusion that compliance in their studies was directly related to the training and investigator–participant relationship. In fact, there is absolutely no empirical evidence of any difference in participant motivation or quality of training between their studies, which they assert yielded good compliance, and our studies that found poor actual compliance (Broderick et al., 2003; Hufford et al., 2002; Stone et al., 2002). In our opinion, Green et al.’s (2006) statement, “These three studies provide clear examples of the ways in which participant burden and participant motivation play key roles in diary studies” (p. 104), has no basis of support from their studies. Having stated that, it is true that Green et al. (2006) have raised the important issue of balancing the tension between encouraging participants to engage fully in the protocol while simultaneously urging them to be honest about missed data and deviations from protocol. Instructions that are excessively demanding and rigid with regard to issues of compliance probably would encourage participants to try to hide their deviations from protocol from the investigator through false reporting. At the other extreme would be the danger of conveying too much permissiveness regarding missing entries or completing entries at a nondesignated time. The current situation is that investigators attempt to communicate with participants in a manner that they believe strikes an effective balance to yield good quality data. Yet, how can researchers objectively assess their skill in affecting participant motivation and compliance? We believe that it may be tempting to view one’s own rapport with research participants as particularly collaborative and to conclude that this will ensure good compliance with protocol. There probably is variation across participants and research laboratories, but we doubt that researchers are capable of an informed self-assessment. The implication of Green et al.’s reasoning is that laboratories that observe lower levels of compliance probably have poorly motivated participants either because of participant characteristics or failure of the researcher to enhance motivation through a collaborative relationship. This assertion could lull researchers into the belief that their diary compliance is good because they perceive their participants to be motivated. There is no empirical basis in the diary literature on which to draw this conclusion.
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Differences in Data Produced by Paper and Plastic Methods There appears to be little controversy about the advantages of electronic data capture—that is, reducing undecipherable written responses, eliminating multiple or invalid responses to single items, and reducing labor and errors in manual data entry (Hanscom, Lurie, Homa, & Weinstein, 2002; Johannes et al., 2000; Palermo, Valenzuela, & Stork, 2004). What is controversial at this point is whether noncompliance (including making ratings distal to the designated collection time, simultaneously backfilling multiple entries, and forwardfilling entries) affects data characteristics, which could ultimately affect testing of experimental hypotheses or correlational relationships. The concern advanced by us and others about paper diaries is that poor compliance, which may be unbeknownst to paper diary researchers, could bias resulting data (Litt et al., 1998; Palermo et al., 2004; Stone et al., 2002). There may be systematic differences between data collected according to the protocol versus data collected at an unknown other time. There is evidence of this consequence in other research areas (Broderick et al., 2004; Johnson et al., 1999; Mazze et al., 1984; Nordmann et al., 2000), and it may be true here as well. If a comparison of data between paper and electronic diaries is made, the two most likely reasons for observed differences in data would be (a) the impact of the mode of question delivery, that is, paper versus electronic, and (b) the impact of differences in compliance with sampling protocol. The studies examining comparability of responses on paper-delivered versus electronic-delivered rating scales indicate that there are no important differences (Bushnell, Martin, & Parasuraman, 2003; Drummond, Ghosh, Ferguson, Brackenridge, & Tiplady, 1995; Ryan, Corry, Attewell, & Smithson, 2002). Thus, let’s conceptually outline the possibilities for data quality as it relates to compliance. First, if a study yielded equal compliance rates for paper and electronic diaries, then we would expect equivalent data quality, because there could not be an effect of noncompliance. Second, if compliance differed between paper and electronic diaries, then there are two logical possibilities: One is that noncompliance does affect data characteristics, and we would therefore expect data differences. The other possibility is that noncompliance does not affect data characteristics, and in this case, no differences in data would be expected. So how should we think about Green et al.’s (2006) studies? We agree that it is possible that compliance was comparable between the paper and electronic diary conditions in these studies because procedures were implemented that could have produced high compliance levels in the paper condition. These procedures include short intervals between diary collections (Study 2) and the use of only
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end-of-day ratings in one of the studies (Study 3). So, if we accept the equivalence of compliance in the paper and electronic conditions, we conclude that the compliance effect was not tested, as compliance did not vary between groups. Under this premise, the conclusion that paper and electronic diary methods have no effect on data quality should be generalized only to studies with equal compliance for paper and electronic diaries. Alternatively, despite Green et al.’s assertion that paper diary compliance was similar to the electronic diary, if the paper diary actually had significantly lower compliance, then the compliance effect would have been tested. Under this premise, we would conclude that data quality was largely unaffected by compliance. Of note, because we do not know which premise is correct, we are unable to draw a conclusion regarding the effect of compliance on data quality. Green et al.’s (2006) statement that “research focused on mean levels, betweenperson differences, and correlations among variables will not be greatly affected by the choice of paper or electronic data collection methods” (p. 104) is, therefore, premature. Green et al. (2006) are to be commended for making an attempt to examine the important question of the impact of compliance on data quality. However, it is going to take studies that are specifically designed to examine the question and that include determination of actual compliance levels to generate the answer. We believe that such studies may show that paper and electronic data are equivalent for some or even for all classes of variables. On the other hand, the impact of compliance may be found to vary by participants’ ability to remember the variables being measured and to accurately report them retrospectively. For example, salient events are more likely to be reliably recalled than are highly repetitive or labile states such as pain or mood. It is likely that new research examining how compliance affects data characteristics will discover that it depends on the types of experiences being measured and many other factors.
Conclusion Diaries and other modes of real-time data collection are becoming an important part of the researcher’s toolbox of techniques (Stone, Shiffman, Atienza, & Nebling, in press; Stone et al., 2000). Although some of these techniques have been available for over 30 years, there has been renewed emphasis on these techniques as behavioral and medical researchers strive to enhance the accuracy and quality of self-report data. Investigating the properties of these methods and instruments is, therefore, timely and should advance their effectiveness and value. The studies presented by Green et al. (2006) and in this commentary make a contribution to the dialogue on diary methodology. Our comments make it clear that there are unsettled issues concerning the use of paper diaries, and like Green and colleagues,
we believe that additional well-designed studies are required to resolve these concerns.
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Received August 25, 2005 Revision received September 25, 2005 Accepted September 27, 2005 䡲
