DATA COLLECTION & MEASUREMENT TECHNIQUES CHAPTER 7 DATA COLLECTION & MEASUREMENT TECHNIQUES (Disarikan dari berbagai sumber)

METHODS OF DATA COLLECTION Monitoring, which includes observational studies. Interrogation/communication studies (survey studies).

TYPES OF SAMPLING DESIGNS Probability Sampel acak – Setiap elemen dalam populasi memiliki probabilitas positif untuk dipilih. Tetapi semakin besar populasi, akan semakin sulit. Nonprobability Sampel tidak acak – Beberapa elemen dalam populasi tidak memiliki peluang untuk dipilih.

PROBABILITY SAMPLING DESIGNS Simple Random Sample Elemen populasi tidak terbatas. Setiap elemen populasi memiliki peluang seleksi yang sederajat dan diketahui.

PROBABILITY SAMPLING DESIGNS Complex Random Sample Elemen populasi terbatas Systematic Sampling Stratified Sampling Proportionate Disproportionate Cluster Sampling Double Sampling

NONPROBABILITY SAMPLING Reasons to use: Procedure satisfactorily meets the sampling objectives. Lower Cost Limited Time Not as much human error as selecting a completely random sample Total list population not available

NONPROBABILITY SAMPLING Sampel nonprobabilitas dapat lebih murah dan cepat, namun kita tidak dapat membuat estimasi statistik yang benar tentang parameter populasi dari metode ini.

NONPROBABILITY SAMPLING DESIGNS Convenience Sampling Elemen populasi tidak terbatas. Pilih sampel sesuka hati. Purposive Sampling Elemen populasi terbatas. Pilih sampel sesuai maksud Judgment Sampling Pilih sampel yang memenuhi kriteria tertentu.

NONPROBABILITY SAMPLING DESIGNS Quota Sampling e.g. Jika hanya wanita yang membeli produk ini, maka pilih sampel wanita saja. Snowball Sampling Pilih elemen awal; elemen berikut akan dipilih oleh elemen ini, dst

SAMPLE SIZE Slovin n = ukuran sampel N = ukuran populasi e = persen kelonggaran ketidaktelitian karena kesalahan pengambilan sampel yang masih dapat ditolerir atau diinginkan misalnya 2%

SAMPLE SIZE Gay Ukuran minimum sampel yang dapat diterima bedasarkan pada desain penelitian yang digunakan, yaitu : Metode deskriptif, minimal 10% populasi untuk populasi yang relatif kecil min 20%. Metode deskriptif-korelasional, minimal 30 subyek. Metode ex post facto (kausal komparatif), minimal 15 subyek per kelompok Metode eksperimental, minimal 15 subyek per kelompok

SAMPLE SIZE Kracjie Sama dengan Slovin, hanya untuk α sebesar 5% dan jumlah populasi N mulai dari sebesar 10 sampai 100.000. Prinsipnya sama dengan Slovin dan besar sampel yang dihasilkan hampir sama besar.

SAMPLE SIZE Harry King Harry king menghitung jumlah sampel menggunakan nomogram dan jumlah populasi maksimum 2000 dengan α bervariasi sampai dengan 15%.

TYPES OF UNIT ANALYSIS Interview Investigator asks specific questions of a respondent and records responses Affords opportunity for in-depth analysis Types Structured - investigator uses a specific set of questions Unstructured - no fixed agenda Has flexibility to diverge from the nature of a question vs. questionnaire “Go where the discussion leads you”

TYPES OF UNIT ANALYSIS Direct observation: Nonbehavioral observation: Record analysis Physical condition analysis Process or activity analysis

TYPES OF UNIT ANALYSIS Behavioral observation: Nonverbal analysis Linguistic analysis Extra linguistic analysis Spatial analysis

TYPES OF UNIT ANALYSIS Advantages: Collect the original data at the time it occurs. Secure information that participants would ignore because it’s so common it is not seen as relevant. Only method available to collect certain types of data Capture the whole event as it occurs in its natural environment. Participants seem to accept an observational intrusion better than they respond to questioning

TYPES OF UNIT ANALYSIS Limitations: Observer or recording equipment must be at the scene of the event when it takes place. Slow process. Expensive process. Most reliable results are restricted to information that can be learned by overt action or surface indicators.

TYPES OF UNIT ANALYSIS Limitations - 2: Research environment is more likely suited to subjective assessment and recording of data than to quantification of events Limited as a way to learn about the past Cannot observe rationale for actions, only actions themselves.

TYPES OF UNIT ANALYSIS Relationship between observer & participant: Direct or indirect observation. Observer’s presence known or unknown to the participant. Observer is involved or not involved with the participant.

TYPES OF UNIT ANALYSIS Methods: Direct Indirect Participant Simple Systematic

TYPES OF UNIT ANALYSIS Data collection: Who What When How Where Event sampling Time sampling When How Where

TYPES OF UNIT ANALYSIS Mailing/e-mailing system (usually with follow-up) Response rates tend to be low Respondent not interested Incomplete responses may require discard Respondent does not fill out the survey correctly requiring discard 40% - 60% response rates common 60% - 80% often considered excellent

TYPES OF UNIT ANALYSIS Because response rates tend to be low a large sample is usually required