This figure describes the data gathering stages of the FDCS:
 
Months after 
baseline
FDCS stage Completion date Number of participants (unweighted numbers **)
-- Sample development May, 1993 3,998 potential dentate participants identified
0 Baseline interview & clinical exam May, 1994 873 participants interviewed & examined (a stratified random sample was taken of the 3,998)
6 Telephone interview November, 1994 849 participants (97% of baseline)
12 Telephone interview May, 1995 819 participants (94% of baseline)
18 Telephone interview November, 1995 805 participants (92% of baseline)
24 In-person interview & clinical exam May, 1996 764 participants (88% of baseline)
30 Telephone interview November, 1996  748 participants (86% of baseline)
36 Telephone interview May, 1997 738 participants (85% of baseline) 
42 Telephone interview November, 1997 724 participants (83% of baseline)
48 In-person interview & clinical exam May, 1998 714 participants (82% of baseline)
54 Telephone interview November, 1998 703 participants (81% of baseline)
60 Telephone interview May, 1999 692 participants (79% of baseline)
66 Telephone interview November, 1999  680 participants (78% of baseline)
72 In-person interview & clinical exam May, 2000  665 participants (76% of baseline)

** The FDCS used a disproportionate stratified random sample.  Therefore, although the weighted and
unweighted sample sizes at baseline were both 873, the weighted and unweighted values post-baseline
do differ somewhat due to differential attrition across strata.

These were the 6-monthly participation/non-participation unweighted distributions:

Time point    Deceased     Medically unable   Participated   Refused   Unreachable       Total
  6 months              9                       3                        849                  4                      8              873
12 months            18                       4                        819                  7                    25              873
18 months            23                       6                        805                12                    27              873
24 months            29                     10                        764                35                    35              873
30 months            36                     15                        748                38                    36              873
36 months            42                     16                        738                40                    37              873
42 months            52                     16                        724                40                    41              873
48 months            60                     15                        714                40                    44              873
54 months            65                     18                        703                44                    43              873
60 months            72                     19                        692                44                    46              873
66 months            83                     19                        680                44                    47              873
72 months            92                     20                        665                46                    50              873

We gathered successfully these types of self-reported and clinical data on our FDCS
participants:
Oral health outcomes measured by clinical examination Self-reported oral health outcomes Subjects’ predisposing and enabling characteristics Subjects’ reported dental care use
Coronal and root caries

Root surface abrasions

Dental/oral signs & symptoms

Chewing ability

Age, area of residence, race, education level Specific dental services used
Bulk restoration fractures

Cusp fractures

Speech interference

Psychosocial impacts

Satisfaction with dental care

Negative aspects of dental care

Dates and reasons for dental visits
Periodontal attachment loss Perceived oral health Importance of dental visits   
Tooth mobility

Tooth loss

Satisfaction with oral health Value/effectiveness of dental care

Value of teeth

 
    Oral hygiene behavior  
    Household income  
    Present financial situation  
    Dental insurance