In other cases household garbage and toilet graffiti has been subject to detailed content analysis.
An Empirical Study: Evaluating Readership of Ads by Analyzing Fingerprints
This paper provides some preliminary results concerning readership of ads based on fingerprints found on trade circulars/flyers mailed to households in a Danish city.
First, a sample of 20 circulars was extracted randomly by using gloves (fear of contamination, self-integrity considerations) at a local recycling center (table 2). Fortunately, the center has separate containers for newspapers and for trade circulars (and weeklies). Next, the sample was sent to and subsequently analyzed by one of the authors who works at the headquarter of The Danish Commissioner of Police. The Commissioner’s office includes a department for analyzing fingerprints. This department contains a small office with employees that specialize at locating fingerprints on paper. Usually these experts look for fingerprints on bad cheques, forged banknotes etc.
However, they do have the expertise to analyze a wide array of paper, including trade circulars for human fingerprints. Fingerprints appear because people sweat. 98% of human sweat consists of water and 2% of amino acid. The water must evaporate prior to analysis since only the “pure” amino acid is traceable. Sweating is an individual characteristic.
Typically, fat, young, temperamental, and nervous individuals sweat more than others. Likewise sweating correlates with season: People are sweating much more on a hot summer day as compared to a cold winter evening. To complicate matters, individuals with (1.) comparable physical and psychological characteristics, and (2.) being exposed to same conditions (temperatures) tend to generate different amounts of sweat.
The total sample involved 30 circulars. They were gathered in January 1999 by use of different procedures. Ten “fresh” items (table 1) were collected immediately after having been studied by a few nonrandom respondents, selected by one of the authors. This author was personally observing and supervising the event, thus ensuring that every page of the involved circulars was touched - via fingertips - by the individual respondent and by none else.
The remaining 20 items were collected at two different days from a container at the local recycling center. On the first day the sky was clear and the weather was rather cold (+4oC, +39oF), while it was raining on the second day (+7oC, +45oF). Although the temperature on the day of collecting the items has little influence on the quality of the fingerprints, wet conditions may deter traces. What counts are the temperature and the conditions prevailing in the environment of the person while she/he is flipping through the pages of the circular. Doing it in front of a fireplace will obviously generate more sweat then when doing it in a cold kitchen. The sample analyzed here was collected during wintertime when people do not sweat much, ceteris paribus. So, the technical conditions for identifying fingerprints were far from ideal.
Analyzing fingerprints on paper is a rather complicated procedure: First, all pages of a circular need to be separated. Second, every page has to be dipped into a liquid called ninhydrin. Third, the wet page must be dried in a high tech device resembling a big microwave oven. Finally, each page has to be scrutinized for fingerprints appearing on the page. Unlike in criminal investigations, it is not necessary to perform a match concerning the uniqueness of an individual fingerprint. What causes interest is whether the page contains a fingerprint or not. It is assumed that a person has been exposed to a page provided that a fingerprint is found on the individual page.
Given the setup chosen it was not possible to make assumptions concerning the characteristics of an individual fingerprint: Did it belong to a small girl or to a grown up male? Additionally, fingerprints appearing on the pages of a given circular may belong to different persons (of a household). According to the expert these problems could have been included in research design. However, including this feature would have made the analysis much more complicated. Moreover, findings derived from such detailed analysis will be of a speculative nature.
In most cases fingerprints only appear a few times across a trade circular. If the circular consists of, say, 32 pages, then one typically will uncover only 2-4 fingerprints across all pages. Furthermore, the frequency of identified fingerprints varies inversely with the number of pages of the individual trade circular: Most fingerprints will be found on the first pages as compared to the last ones.
Nevertheless it is reasonable to assume that the person who has left a few fingerprints, say, on the first four pages indeed has been flipping through the whole circular - although no traces are to be found on the remaining 28 pages.
For methodological reasons the front and rear page of each circular were excluded from analysis since they may have been touched (contaminated) by the messenger (an errand boy on a bike) or by the person of the household who brought the circular to the recycling center. Unlike his wife (her husband), there is a chance that he (she) himself (herself) never read it.
The study reported on here is a pilot study and is part of a far more comprehensive project being under preparation. The purpose of the pilot study has been to generate knowledge and experience concerning the measurement of fingerprints on circulars.
Table 1 displays the findings of the analysis of fingerprints with regard to five non-randomly selected respondents. ID-numbers 01/02, 03/04, 05/06, 07/08 and 09/10 refer to the same respondent, respectively. Each respondent was exposed to two circulars. Person 01/02 refers to one of the authors. 01 was read immediately after spending 20 minutes in a sauna. 02 was studied after having walked around for 20 minutes outside a Helsinki hotel in early January only wearing a T-shirt (-10oC).
The supposition that a person generates more sweat and thus more finger-imprints when he sweats as compared to when he freezes, was confirmed. However, the “sample” consisted of one (!) person. Numbers in brackets in the far right columns of table 1 relate to the total number of fingerprints traced on the circular, including front and rear page. Unfortunately, these fingerprints could relate to someone different from the respondent (see above). Therefore, these gross-estimates were not used for statistical and computational purposes. Two respondents (03/04 and 05/06) were exposed when the room temperature was 21oC, while the other two (07/08 and 09/10) were exposed at 25oC.
Findings based on the Empirical Sample
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∙ One respondent (03/04) provided no valid fingerprint.
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∙ Four circulars (03, 04, 08, 09) contained no valid fingerprints
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∙ Two circulars (04, 08) had no fingerprints whatsoever (even not on front/rear page)
Concerning four respondents 03/04, 05/06, 07/08, 09/10 we can make the following estimates: In total respondents were flipping through 112 pages. For each of the eight circulars we must detract the front and the rear pages. Thus, we end up with 96 valid pages. Across these pages the expert found seven fingerprints. Stated differently, 7% of all pages analyzed contained fingerprints (if we allow for the front and rear page to be included the figures rise to 11%). This computation can be repeated once for every respondent. The number of fingerprints varies considerably from respondent to respondent. For instance Respondent 05/06 is much more successful with regard to generating traces as compared to 03/04.
Table 2 displays results concerning the twenty randomly selected circulars. We have no background information about the readers of these circulars. The sample consisted of 860 pages and 55 valid fingerprints were identified. 60% of the circulars identified (12 out of 20) contained at least one valid fingerprint. We assume that the 60% is a lower level with respect to readership. Regarding the remaining eight circulars (seven of them contained no fingerprint at all) we cannot state that they have not been read.
We can only say that we were not able to identify any fingerprints. Remember that respondent 03/04 in table 1 did not provide any valid fingerprints although one of the authors observed her while performing the task. Note also that no valid fingerprints were identified on ID 30. However, it must have been studied, since someone had encircled the price of a product with a pen.
Once more we observe significant variation across circulars. ID’s 17, 23, 25 and 28 produced lots of fingerprints, while others like 11, 16, 20, and 24 only left a single fingerprint. We can just speculate about the underlying reasons for this (see above).
Discussion
Our analysis of fingerprints indicates that at least 60% of the circulars must have been studied by at least one individual. The remaining 40% may (1.) have been read by one or more individuals who have left no trace of the task, (2.) they may have been discarded by the household unread. (3.) There is a chance, however, that the circular never made its way to the prospects: It is usual that the person distributing the circulars is equipped with too many circulars as compared to households or addresses en route.
Since these printed ads typically have a life span of a single week, they are to be compared with perishable goods. Consequently, the messenger - often a teenager on a bike and/or with a box barrow - will carry the remaining undistributed circulars to the recycling center and throw them into the container. Usually such circulars are easy to identify because they show up in the container as stacks of the same circulars, whereas other circulars are distributed randomly across the container (in the present study care was taken to circumvent this problem).
A final note: Are observational approaches less culture-bound than survey methods?
The above study was carried out in a Northern European country. It is obvious to question whether the involved research approach is applicable to the study of circular-readership in countries having a different cultural background like, say, Mexico, Morocco, and South Korea. Everything else being equal we assume that unobtrusive methods are less sensitive to cultural peculiarities than survey methods. The rationale behind this argument is that observational methods are not dependent on the accuracy and believability of human communication. It is well documented that survey-respondents often do not provide valid responses due to a set of reasons (see above).
If differences in the cultural frame of reference between two countries are detected, then it is at least probable that these differences affect the way respondents percept the communication “imbedded” in the questionnaire. Comprehensive studies by Segall, Campbell, and Herskovits (1966) and Hall (1976) indicate that many problems in international research are caused by simple misunderstandings in the process of cross-cultural communication.
As a matter of fact this potential source of error does not at all appear if a cross-cultural study is based on sheer observation. A fingerprint in, say, Mexico, is compatible to a fingerprint in Denmark and Japan.
However, it is fair to assume - so far unproven, though - that it will be easier to detect fingerprints in countries near the equator as compared to countries north of the polar circle.
That is simply because people sweat when it is very hot while they do not sweat much when it is cold and when they freeze. Therefore, compatible respondents may generate different frequencies of fingerprints due to differences in climate and temperature. But if two countries have almost the same climate and the study is carried out under comparable conditions (i.e. analysis of selected popular supermarket flyers) then one should assume that cross-cultural differences in the amount of identified fingerprints reflect differences in readership of the involved circulars. Once more: Everything else being equal.
