long_admins <- get_administration_data(original_ids = TRUE) %>%
  gather(measure, vocab, comprehension, production) %>%
  filter(language == "English", longitudinal) 

first_child <- long_admins %>%
  filter(original_id == first(original_id), measure == "production")

kable(first_child)
original_id data_id age language form birth_order ethnicity sex norming longitudinal source_name mom_ed measure vocab
E0002 50375 13 English WG NA NA Female FALSE TRUE Thal NA production 6
E0002 51016 16 English WG NA NA Female FALSE TRUE Thal NA production 24
E0002 56169 16 English WS NA NA Female FALSE TRUE Thal NA production 24
E0002 56822 28 English WS NA NA Female FALSE TRUE Thal NA production 433