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. 2012 Apr 30;67(12):1427–1438. doi: 10.1093/gerona/gls108

Appendix 2. Item Difficulty and Fit Statistics

Domain Items Parameters
Discrimination Location Difficulty
a1 a2 a3 c1 c2 c3
Participation restriction Taking part in active recreation? 1.92 0.56 0 0.87 −0.7 −2.33 −0.72
Taking part in a regular fitness program? This may include walking for exercise, stationary biking, weight lifting, or exercise classes. 1.64 0 0.03 2.28 1.02 −0.46 0.95
Caring for a sick or disabled adult? 1.93 0 −0.33 2.49 1.14 −0.51 1.04
Driving yourself in a car? 1.74 −0.41 0 1.75 1.34 0.24 1.11
Going on the sort of trips and holidays you want to go on? 2.19 0.24 0 3.27 1.13 −0.69 1.24
Having a sexual relationship? 1.25 0.44 0 2.37 1.28 0.27 1.31
Working at a volunteer job outside your home? 2 0 0.16 2.7 1.46 0.25 1.47
Providing care or assistance to others? This may include providing personal care, transportation, and running errands for family members and friends. 3.07 0 −0.4 3.5 1.92 −0.51 1.64
Getting housework done by yourself when you want it done? 2.01 0 0.44 3.63 1.79 −0.36 1.69
Traveling out of town for at least an overnight stay? 2.19 0.19 0 3.15 1.59 0.32 1.69
Filing your taxes? 1.37 0 0.28 3.02 1.68 0.69 1.80
Traveling by bus, train or ferry? 1.96 −0.34 0 3.48 1.85 0.24 1.86
Completing forms for insurance or disability benefits? 1.19 0 0.27 3.41 2.07 0.17 1.88
Going to parks or other outdoor recreational areas? 2.1 0.09 0 3.53 2.07 0.22 1.94
Taking care of the inside of your home? This includes managing and taking responsibility for homemaking, laundry, housecleaning, and minor household repairs. 2.28 0 0.47 4.26 2.2 −0.13 2.11
Inviting people into your home for a meal or entertainment? 1.8 0.87 0 4.05 2.09 0.46 2.20
Going to a sport, social, or other club? (female) 2.09 0.93 0 4.05 2.27 0.38 2.23
How much work you do (including work at home)? 2.25 0 1.74 6.09 2.58 −0.89 2.59
Baking or cooking something special for others? 2.32 0 0.02 4.03 2.87 0.95 2.62
Your ability to meet the needs of those who depend on you? 2.76 0 0.28 5.03 2.87 0.19 2.70
Doing things for fun outside your home? 2.06 0.82 0 4.97 2.7 0.64 2.77
Taking part in organized social activities? 2.1 0.96 0 4.7 2.95 0.75 2.80
Writing checks, paying, bills, balancing checkbook, keeping financial records? 1.37 0 0.66 4.48 2.7 1.25 2.81
Taking care of household business and finances? This may include managing and taking responsibility for your money, paying bills, dealing with a landlord or tenants, dealing with utility companies or governmental agencies. 1.53 0 0.55 4.57 2.79 1.14 2.83
Working on a hobby or project? 2 0.77 0 5.05 2.86 0.69 2.87
Reading books, magazines or newspapers? 1.2 0.5 0 4.35 2.8 1.5 2.88
Going to a sport, social, or other club? (male) 2.84 0.63 0 5.43 2.87 0.43 2.91
Doing your job the way you want to? (≥75 y) 2.63 0 1.56 5.78 3.36 0 3.05
Getting minor housework done by yourself? 2.29 0 0.5 5.08 3.34 0.8 3.07
Doing the work you want to do? 3.16 0 2.58 7.56 2.73 −1.05 3.08
Doing things for your grandchildren? 2.36 0 −0.01 5.25 3.4 0.67 3.11
Doing your job the way you want to? (<75 y) 2.27 0 1.52 6 3.31 0.12 3.14
Taking your car in for regular maintenance? 2.73 0 −0.03 4.53 3.46 1.94 3.31
Doing things for your spouse? 3.07 0.1 0 5.99 3.45 0.72 3.39
Seeing people as often as you want? 2.45 1.21 0 6.68 3.31 0.38 3.46
Doing things for your friends? 2.88 0 0.07 5.8 3.75 0.85 3.47
How much difficulty do you currently have keeping in touch with others with letters, phone, or email? 1 1.5 0 5.86 3.46 1.46 3.59
The amount of time you spend visiting friends? 2.85 1.57 0 6.23 3.65 0.93 3.60
Doing your job as carefully and accurately as others with similar jobs? 2.32 0 1.27 5.96 3.94 0.95 3.62
The amount of time you spend doing work (include work at home)? 3.16 0 3.06 8.84 3.14 −1.02 3.65
Playing cards or games such as bingo? 1.71 0.96 0 5.05 3.9 2.13 3.69
Taking care of your own health? This may include managing daily medications, following a special diet, scheduling doctor’s appointments. 1.51 0 0.72 5.93 3.63 1.61 3.72
Visiting friends and family in their homes? (≥75 y) 2.72 0.78 0 6.01 3.71 1.75 3.82
Taking care of local errands? This may include managing and taking responsibility for shopping for food and personal items, and going to the bank, library, or dry cleaner. 3.47 0 −0.2 6.09 4.3 1.92 4.10
Going out with others to public places such as restaurants or movies? 2.84 0.93 0 6.3 3.86 2.16 4.11
Preparing meals for yourself? This includes planning, cooking, serving and cleaning up. 2.83 0 0.33 5.94 4.33 2.19 4.15
Getting along with other people you live with? 1.23 1.32 0 6.53 4.53 2 4.35
Visiting friends and family in their homes? (<75 y) 3.23 1.31 0 6.71 4.38 1.99 4.36
The amount of contact you have with family and friends? 2.38 1.65 0 7.41 4.15 1.53 4.36
Preparing your own meals with help? 1.99 0 0.4 6.11 4.58 2.6 4.43
Getting together with your neighbors? 2.53 1.01 0 7.27 4.37 1.71 4.45
Doing the work that is really important to you (include work at home)? 3.71 0 2.92 9.28 4.17 −0.09 4.45
Going outside the home, for example to shop or visit a doctor's office? 2.68 0 0.03 7.15 4.62 2.4 4.72
Taking care of your own personal care needs? This includes bathing, dressing, and toileting. 2.09 0 0.55 6.95 4.53 2.74 4.74
Voting in elections? 1.99 0.82 0 6.45 4.7 3.45 4.87
Talking to people close to you? 1.71 2.11 0 8.77 5.11 3.06 5.65
Having a close friendship? 1.92 2.54 0 8.79 5.41 3.01 5.74
Maintaining a friendship? 2.36 3.15 0 10.3 7.13 3.93 7.12
Activity limitation Running 1/2 mile or more? 1.59 0 1.71 −2.8 −4.6 −8.58 −5.33
Hiking a couple of miles on uneven surfaces, including hills? 2.79 0 2.75 −6.9 −4.3 −2.13 −4.43
Lifting 50 pounds (eg, a large full suitcase) or more? 1.93 0 0.6 −1.6 −3 −4.77 −3.13
Running a short distance, such as to catch a bus? 2.2 0 1.94 −1.3 −2.3 −4.37 −2.64
Taking a 1 mile, brisk walk without stopping to rest? 2.39 0 2.26 −0.9 −2.4 −4.17 −2.51
Going up a flight of stairs outside, without using a handrail? 3.38 0 3.18 0.06 −2 −5.04 −2.33
Lifting 25 pounds from the ground to a table? (eg, dog food or a large bag of fertilizer)? (female) 2.06 0 0.6 −0.3 −1.8 −4.29 −2.12
Carrying something in both arms while climbing a flight of stairs (eg, laundry basket)? 3.06 0 2.3 −0.2 −1.6 −4.34 −2.04
Standing for one hour? 2.2 0 0.9 −0.1 −2 −3.95 −2.00
Walking on a slippery surface outdoors? 1.74 0 1.4 0.87 −1.8 −4.84 −1.93
Walking up steep unpaved inclines (eg, steep gravel driveway)? 2.53 0 1.91 1.08 −1.7 −4.47 −1.71
Getting up from the floor (as if you were laying on the ground)? 2.62 0 0.86 1.18 −1.5 −4.09 −1.47
Going up and down 3 flights of stairs inside, using a handrail? 2.25 0 1.57 0.99 −1.1 −3.17 −1.08
Opening a stuck window? (female) 1.51 0 0.31 1.08 −0.8 −3.3 −1.02
Descending 3–5 steps without a handrail? 2.99 0 2.52 0.88 −0.5 −2.88 −0.84
Walking a mile, taking rests as necessary? 2.72 0 2.23 0.67 −0.7 −2.28 −0.75
Getting into a squatting position (eg, when gardening)? 2.31 0 0.62 1.18 −0.5 −2.69 −0.68
Climbing 3 to 5 steps without a handrail? 3.29 0 2.73 1.18 −0.4 −2.66 −0.62
Unscrewing the lid off a previously unopened jar without using any devices? (female) 1.09 0.59 0 1.78 −0.2 −2.99 −0.46
Unscrewing the lid off a previously unopened jar without using any devices? (male) −0 −0.04 0 3.78 1.46 −0.59 1.55
Walking several blocks (several hundred yards or lengths of a football field)? 2.79 0 2.03 1.48 −0.5 −2.09 −0.36
Cutting your toenails? 1.5 0.41 0 0.87 −0.1 −1.58 −0.26
Standing for 20 min (eg, waiting in a line)? 2.61 0 0.8 1.86 0.03 −2.32 −0.14
Fastening a necklace behind your neck? 1.63 0.79 0 1.78 0.19 −1.98 0.00
Using a step stool to reach into a high cabinet? 2.67 0 1.04 1.38 0.38 −1.38 0.13
Unloading a car trunk or hatchback (eg, packages or equipment)? 2.83 0 0.67 1.74 0.57 −1.54 0.26
Lifting 25 pounds from the ground to a table? (eg, dog food or a large bag of fertilizer)? (male) 0.5 0 −0.43 1.8 0.36 −1.28 0.29
Walking on an uneven surface (eg, grass, dirt road or sidewalk)? 2.52 0 1.48 3.12 0.28 −2.53 0.29
Carrying 2 plastic grocery bags with handles at your side for 50 feet? 3.2 0 1.47 1.75 0.7 −1.37 0.36
Carrying a large object, requiring two hands (eg, tray of food) while walking? 3 0 1.01 1.6 0.76 −1.27 0.36
Fastening clothing behind your back? 2.13 0.74 0 2.18 0.76 −1.49 0.48
Crossing the road at a 4-lane traffic light with curbs? 2.28 0 1.29 2.24 0.56 −1.21 0.53
Opening a heavy, outside door? 2.29 0 0.29 2.86 0.81 −1.96 0.57
Sitting down in a low, soft couch? 2.23 0 0.21 2.71 0.84 −1.01 0.85
Stepping on and off a bus? 2.68 0 1.07 2.93 1.14 −1.51 0.85
Using a computer? 0.75 0.74 0 1.92 1.01 −0.3 0.88
Pounding a nail in straight with a hammer to hang a picture? 1.92 0 0.1 2.21 1.08 −0.6 0.90
Opening a stuck window? (male) 0.58 0 −0.56 2.55 1.19 −1.01 0.91
Going up and down a flight of stairs inside, using a handrail? 2.84 0 1.55 3.24 1 −1.31 0.98
Ripping open a package of snack food (eg, cellophane wrapping on crackers) using only your hands? 1.33 0.62 0 3.59 1.29 −1.65 1.08
Bending over from a standing position to pick up a piece of clothing from the floor ? 2.61 0 0.29 3.08 1.23 −1.08 1.08
Cleaning up spills on the floor (eg, with a rag)? 3.13 −0.5 0 3.49 1.2 −1.29 1.13
Holding a screw and screwing it tight with a manual screwdriver? 1.77 0 0.08 2.44 1.47 −0.43 1.16
Walking one block (about 100 yards or the length of one football field)? 2.64 0 1.76 2.76 1.5 −0.61 1.22
Making a bed, including spreading and tucking in bed sheets? 2.28 −0.03 0 3.23 1.39 −0.79 1.28
Lifting 5 pounds from the ground to a table (for example, a bag of flour or sugar)? 2.69 0 0.54 2.7 1.45 −0.32 1.28
Cleaning the floor using a broom and dustpan? 3.21 −0.57 0 2.92 1.58 −0.49 1.34
Walking backwards 3 steps? 2.24 0 0.82 2.54 1.64 −0.1 1.36
Remembering a list of 4 or 5 errands without writing it down? 0.79 0.17 0 3.7 1.51 −1.01 1.40
Reaching behind your back as if to put a belt through a belt loop? 2.88 0.74 0 3.21 1.75 −0.54 1.47
Walking quickly indoors to answer the telephone? 3.18 0 1.53 3.46 1.95 −0.58 1.61
Picking up a kitchen chair and moving it, in order to clean? 2.99 0 0.73 3.1 2.1 −0.28 1.64
Reaching overhead while standing, as if to pull a light cord? 1.93 0 0.48 3.17 1.81 0.07 1.68
Standing up from an armless straight chair (for example, a dining room chair)? 2.57 0 0.67 3.9 2.04 −0.74 1.73
Biting and chewing on hard foods (eg, a firm apple or celery)? 1.05 0.59 0 2.95 1.92 0.38 1.75
How much help from another person do you currently need getting into a tub? 2.27 0 0.64 2.45 1.69 1.13 1.76
Using an escalator? 2.6 0 1.41 2.81 2.17 0.48 1.82
Standing, while leaning on the sink for 10 minutes? 2.26 0 0.4 3.66 2.03 −0.07 1.87
Stepping up and down from a curb? 2.77 0 1.27 4.37 2.23 −0.79 1.94
Turning over in bed (including adjusting bedclothes, sheets and blankets)? 2.31 0 0.03 4.36 2 −0.18 2.06
Getting into and out of a car/taxi (sedan)? 2.64 0 0.54 5.16 2.12 −1 2.09
Pouring from a large pitcher? 2.02 0.52 0 4.47 2.32 −0.21 2.19
Tying shoes? 3.18 0.42 0 3.6 2.46 0.52 2.19
Walking around inside a building (50 ft.) on the same level (for example, hospital hallway, around a doctor’s office or supermarket)? 3.17 0 1.18 3.94 2.64 0.49 2.36
Searching a crowded grocery shelf to find the brand of cereal you prefer? 1.21 0.27 0 4.14 2.68 0.28 2.37
Putting on socks? 2.49 0.27 0 3.99 2.58 0.54 2.37
Washing dishes, pots, and utensils by hand while standing at sink? 2.96 −0.19 0 4.01 2.71 0.47 2.40
How much help from another person do you currently need getting into a tub using a tub seat? 1.98 0 0.52 3.25 2.53 1.45 2.41
Operating an ATM (automatic teller) to get cash or make deposits? 0.9 0.65 0 3.35 2.64 1.28 2.42
Reaching behind you to get your seatbelt? 2.26 0 0.03 4.8 2.58 0.18 2.52
How much help from another person do you currently need climbing a full flight of stairs with a railing? 3.04 0 1.73 3.72 2.68 1.63 2.68
Reaching into the back pocket of a pair of pants? (<75 y) 0.48 0 −0.48 4 2.64 1.42 2.69
Looking up a phone number or address in the phone book or in your own address book? 1.07 0.39 0 4.24 2.81 1.06 2.70
Putting on a (button down) shirt or a blouse? (<75 y) 0 0.13 0 4.47 2.45 1.2 2.71
Washing and rinsing your hair? 2.57 0.71 0 3.61 2.85 1.7 2.72
Washing your lower body while giving yourself a sponge bath? (male) −0.1 −0.25 0 4.08 2.68 1.43 2.73
Sitting down in an armless straight chair (eg, a dining room chair)? 2.8 0 0.32 4.59 2.93 0.86 2.79
Using a washer and dryer, including loading clothes, and setting the dials? 2.21 0.43 0 3.7 3.06 1.78 2.85
Chopping or slicing vegetables (eg, onions or peppers)? 2.24 0.78 0 4.44 3.26 1.05 2.92
Keeping track of time (eg, using a clock)? 1.08 0.33 0 4.1 1.75 2.93
Styling your hair? 2.19 1.43 0 4.42 2.92 1.47 2.94
Carrying a small object in one hand (eg, something fragile or a glass of water) while walking indoors? 2.98 0 0.88 4.16 3.52 1.24 2.97
Cleaning kitchen surfaces thoroughly (eg, stove, sink, or counter tops)? 2.22 0.04 0 5.13 3 0.99 3.04
Moving from lying on your back to sitting on the side of the bed? 2.82 0 0.01 6.45 3.04 −0.32 3.06
Walking around one floor of your home, taking into consideration doors, furniture, and a variety of floor coverings. 2.73 0 0.71 4.37 3.64 1.29 3.10
Using a microwave to heat up foods? (male) 1.28 0.78 0 4.16 3.73 1.55 3.15
Standing for at least one minute? 2.83 0 0.64 4.7 3.86 1.47 3.34
Holding a book while reading? 1.93 0 −0.32 5.03 3.79 1.33 3.38
Trimming and filing your fingernails? 2.01 1.58 0 4.69 3.67 1.99 3.45
Opening car doors? 2.88 0 −0.1 4.81 4.08 1.58 3.49
Holding a full glass of water in one hand? 1.95 0 −0.21 5.04 3.8 1.75 3.53
Zipping a jacket? 1.81 1.11 0 5.38 3.89 1.44 3.57
Reaching into the back pocket of a pair of pants? (≥75 y) 2.58 0 −0.15 5.45 3.6 1.73 3.59
Holding a plate full of food? 2.51 0.89 0 6.03 3.72 1.21 3.65
Using common utensils for preparing meals (for example, can opener, potato peeler, or sharp knife)? 2.48 1.43 0 5.68 3.86 1.49 3.68
Putting on a (button down) shirt or a blouse? (≥75 years) 2.02 0.93 0 6.05 3.79 1.62 3.82
How much help from another person do you currently need stepping into a shower? 3.05 0 1.07 5.27 3.68 2.55 3.83
Doing zippers, snaps, or hooks on pants? 3.11 1.36 0 6.04 4.23 1.54 3.94
Putting on long pants (including managing fasteners)? 3.06 0.48 0 6.64 3.88 1.36 3.96
Putting on makeup accurately (for example, lipstick, foundation, eyeliner)? 1.63 0.74 0 6.09 4.19 1.75 4.01
Putting on a coat or jacket? 3.05 1.02 0 7.9 4.7 1.56 4.72
Putting on a pullover shirt? 2.55 1.23 0 7.66 4.61 1.92 4.73
Washing your lower body while giving yourself a sponge bath? (female) 2.64 0.65 0 7.3 5.03 2.23 4.85
Applying spreads to bread using a knife? 2.39 1.15 0 6.65 5.15 3.01 4.94
How much help from another person do you currently need moving from a bed to a chair (including a wheelchair)? 3.13 0 0.35 6.42 3.54 4.98
Washing your upper body while giving yourself a sponge bath? 3 0.57 0 7.42 5.12 2.44 4.99
Using a microwave to heat up foods? (female) 2.28 1.23 0 6.55 3.89 5.22
Preparing the toothbrush and brushing teeth? 2.27 1.21 0 7.23 3.78 5.51
Cutting your own food (such as meat, fruit, etc.)? 2.98 2.24 0 8.1 5.86 3.54 5.83
Combing and parting hair? 3.24 1.64 0 7.97 6.51 3.42 5.97
Using a spoon to eat a meal? 2.15 1.93 0 7.55 4.54 6.05
Using a fork to eat a meal? 2.25 1.85 0 8.24 7.05 4.28 6.52
How much help from another person do you currently need managing toileting aftercare, including wiping yourself and putting clothes back on? 4.39 0 0.18 9.38 6.46 4.39 6.74

*Difficulty, or location parameters were estimated using a multidimensional logistic graded response model, which estimates both the discrimination parameters and the ordered location parameters for each item. The marginal maximum likelihood estimation was used to estimate the item parameters. For the bifactor model in this study, there are three discrimination parameters for each item: one for the general factor (a1) and one for each of the two sub-factors (a2 and a3).

†Difficulty parameters were estimated by calculating the mean of the ordered location parameters (c1, c2, and c3) of an item.